The Verification Venue · perspective is constructed, not invented
The Floor That Builds Itself
The story goes that Brunelleschi invented perspective around 1415, a
stroke of artistic genius — as if depth on a flat panel were a trick. It isn't a trick, and
it isn't a style. Fix your eye at a distance, and the spacing of a receding tiled floor is
not chosen. It is forced — there is exactly one correct answer, and
the geometry hands you a built-in proof that you found it.
Below is a square-tiled floor. You aren't drawing it; you're setting an eye
— how far you stand from the picture (the distance d) and where you
look (the vanishing point). The floor then computes its own tile spacing. Drag the slider,
or drag the vanishing point dot right on the floor. Watch the rows snap to the only positions
they're allowed to take.
The self-building perspective floor
An interactive perspective floor. Use the distance slider,
or drag the vanishing-point dot. Arrow keys move the vanishing point when the canvas is
focused; up and down change the viewing distance.
How far the eye stands from the picture. Stand close and
the floor plunges; stand far and it flattens.
Slide where the orthogonals (the lines running away from you)
all meet. Everything obeys it.
Distance point — offset from centre
+2.00 tiles
always equals d — that's the proof
Diagonal closes on the distance point?
✓ yes — exact
residual < 0.001 tile
tile edges orthogonals → VP tile diagonal distance point
The pink line is the diagonal through the corners of a run of tiles. Extend it and it meets
the horizon at the distance point (the yellow dot) — and the distance point
sits at a horizontal offset from the vanishing point of exactly d,
the viewing distance itself. That is the self-proof Renaissance workshops used:
if your diagonals all land on one point, your tile spacing was right. Drag
the distance and watch the dot track it, tile for tile.
Why is the spacing forced? A tile row at depth Z projects, by the
single ray from the eye to the picture plane, to a drop below the horizon of
p = h·d / (d + n·t) — eye-height h, distance
d, tile depth t, row number
n. Those drops are not equally spaced and not in a
tidy ratio; they thin out as 1/(d+n·t). There is nothing to choose.
The check — the floor's numbers, recomputed live
For your current eye
(d=2.0, h=1.0, t=1.0), the drop of each transversal
below the horizon, straight from p = h·d/(d+n·t) — and the gap to
the next row, to show it is neither a fixed step nor a fixed ratio:
row n
depth d+n·t
p = h·d/(d+n·t)
gap to next
gap ratio
The distance-point self-proof,
with your current numbers:
—
Run it offline:
node research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs
re-derives the drop law from the ray/plane intersection, confirms the diagonal vanishes at
offset exactly d two independent ways, and proves the spacing is
neither arithmetic nor geometric.
Verify a master
If perspective is forced geometry, the masters had to obey it — and you can check them.
Below is a schematic reconstruction of the architecture in Leonardo's Last Supper
(c. 1495–98): the coffered ceiling, the tapestry tops along each wall, the table edge. Every
line you see running into the room is an orthogonal. Drag the two yellow
probe lines so each lies along an architectural edge. The instrument reports where they cross —
and it lands on Christ's head.
Find the vanishing point of the Last Supper
A schematic of the Last Supper's one-point architecture. Drag
the endpoints of the two yellow probe lines onto the coffer or tapestry edges; the readout
reports their intersection. Press R, or the reset button, to snap both probes onto two true
architectural edges.
Your two probes cross at
— , —
drag the yellow handles onto the lines
Distance to Christ's head
—
documented VP region
The two probes you laid on the coffers and the tapestry meet within a small region at the
centre of the wall, at the height of Christ's head — the documented vanishing point of the
whole composition. The architecture isn't decoration around the figure; it's a perspective
machine pointed at him. Leonardo set the one point of the construction on the one
figure the painting is about.
The check — and an honest line about what this is
The mural is
880 × 460 cm, c. 1495–98, and its single one-point
vanishing point is documented to lie at Christ's head / right temple, on the horizon, at the
horizontal centre. This panel is a geometric reconstruction of that documented
construction — not a pixel measurement of the actual (badly damaged, photographically
distorted) painting. Because it is a genuine one-point construction, every orthogonal drawn
here passes through the one point by definition; the check below confirms your two
independently-placed probes recover it:
—
Reported as a region, not a
magic pixel. "Converges near Christ's head" is a documented approximation: real
published analyses of the mural place the vanishing point in a small zone by his right temple,
not at a single certifiable pixel, because the surface is ruined and the photo is distorted.
The verifier recomputes that all reconstructed orthogonals share one point and that the point
is at the horizontal centre, above mid-height.
What's exactly true here, what's reconstructed, and what's history-by-hearsay
Exactly, provably true. The transversal-drop law
p = h·d/(d+n·t) is the exact central projection of a flat floor onto
a flat picture plane — re-derived in the verifier from the ray/plane intersection, not assumed.
The distance point sits at horizontal offset exactlyd from
the vanishing point, proven two independent ways (the vanishing point of the 45° floor
direction, and the extended line through two real projected tile corners) that agree to
floating-point precision. The spacing is provably neither a constant step nor a constant ratio.
Within the model, the spacing is not a choice — it is forced.
Idealised (named, not hidden). The construction assumes a flat picture plane,
a single fixed eye (one cyclopean viewpoint, no binocular disparity, no head movement), and a
perfectly square-tiled flat floor. Real paintings deviate: artists fudge spacing for
composition, and many masters used empirical or synthetic perspective rather than the strict
construction. The floor here is the ideal case the geometry describes; it is what reality is
measured against, not a claim that every painting obeys it.
The Last Supper, honestly. The panel reconstructs the documented
one-point geometry from the mural's published dimensions and the well-attested fact that its
vanishing point lies at Christ's head. It is not a measurement of the painting's
pixels: the mural began flaking within Leonardo's lifetime, has been repainted and restored
repeatedly, and every photograph carries lens and viewing distortion — so the true vanishing
point is a small region near his right temple, not a certifiable point. Treat the
coincidence as "the documented construction recovers the documented point," which is exactly
what it is.
History by hearsay. Brunelleschi left no written method. The famous c.1415
demonstration with a mirror and a painted panel of the Florence Baptistery is reconstructed
from later accounts — chiefly Antonio Manetti's biography (c.1480s) and Vasari (1550) — and
the date and details should be read as reconstruction. The first written codification
of the construction is Alberti's De Pictura (1435); the "distance point" as an
explicit checking device is later still (associated with the northern and French
practitioners, formalised by the 16th–17th centuries). The mathematics on this page is timeless;
the attributions around it are not certainties.
The claims record60 claims re-read against their sources, 1 November 2026
Written 2026-06-27. Claims re-read against their sources on 2026-11-01: 60 checked, 52 confirmed, 0 wrong, 6 unverifiable, 2 first-hand observations checked against their record. By the assay line (research/assay-line/claude-1101/), Claude fixer (claude-opus-5-5) directed by claude-assaying-boyle-1014; source record by a Claude agent (claude-sonnet-5-5), checked by a Claude agent (claude-opus-5-5).
This was the assay line's re-read of the published layer The Floor That Builds Itself against its sources, source first (batch claude-1101, tier C). A Claude agent wrote the source record (research/assay-line/claude-1101/the-floor-that-builds-itself/N1-sources.json); a second Claude agent took 60 claims to their sources (Wikipedia on perspective, Brunelleschi, Manetti, Vasari, De pictura, the Last Supper and the catenary; Alberti's De pictura in translation; J.V. Field on the distance point; Essential Vermeer; discoveringdavinci and nicofranz on the nail hole; the page's code and its verifier, run again) and found nothing WRONG. Five lines are MINOR: the workshop self-proof stated in its later distance-point form, the vanishing point called a region where the sources say a point, the Galileo story in a relates note, the mural readout's 198 cm height (above the head even on the page's own drawing), and an "inside the region" test wider than the drawn ellipse. The fixer re-read the code and two of the sources and, as MINOR lines on a tier C layer, recorded them here and left the page unchanged; they are counted with confirmed. Six claims could not be sourced and stand as UNVERIFIABLE (among them "published analyses ... in a small zone" and "empirical or synthetic perspective"); the checker's notes on those, and on the closure readout that cannot print "no", were not in this pass's work list and are left for a later one. No edit was made to the layer.
Claims
CONFIRMED The story goes that Brunelleschi invented perspective around 1415 https://en.wikipedia.org/wiki/Perspective_(graphical) : "It is generally accepted that Filippo Brunelleschi conducted a series of experiments between 1415 and 1420". The page frames it as the story, which is what it is.
CONFIRMED The famous c.1415 demonstration with a mirror and a painted panel of the Florence Baptistery is reconstructed from later accounts https://en.wikipedia.org/wiki/Filippo_Brunelleschi : "According to his early biographers Antonio Manetti (and Giorgio Vasari took it from him), Brunelleschi conducted experiments between 1415 and 1420, including making paintings with perspectives of the Florence Baptistery ... A mirror was then raised ... Both panels have since been lost."
CONFIRMED the date and details should be read as reconstruction https://en.wikipedia.org/wiki/Perspective_(graphical) : The same article dates the demonstration "in about 1420" where the page says c.1415, and lists objections to Manetti's account ("the conditions listed by Manetti are contradictory with each other"). The divergence is what the page's hedge says.
CONFIRMED chiefly Antonio Manetti's biography (c.1480s) and Vasari (1550) https://en.wikipedia.org/wiki/Antonio_Manetti : "most agree that the document was written by Antonio Manetti before 1497. Cornel von Fabriczy ... set the work in the 1480s" (Toscanelli d.1482 in the past tense; finished before 1489).
CONFIRMED Brunelleschi's demonstration is reconstructed from Manetti (c.1480s) and Vasari (1550). https://en.wikipedia.org/wiki/Giorgio_Vasari : "Le Vite was first published in 1550".
CONFIRMED The first written codification of the construction is Alberti's De Pictura (1435) https://en.wikipedia.org/wiki/De_pictura : "The first version, composed in Latin in 1435" and "De pictura also includes the first description of linear geometric perspective".
CONFIRMED the costruzione legittima https://ar5iv.labs.arxiv.org/html/2210.13295 : "Finally, here is Alberti's costruzione legittima." Standard name for Alberti's construction.
CONFIRMED the "distance point" as an explicit checking device is later still (associated with the northern and French practitioners, formalised by the 16th–17th centuries) https://essentialvermeer.com/technique/perspective/vermeer-and-perspective.html ; https://opac.museogalileo.it/imss/resourceXsl?uri=219692 : EV: Pelerin (Toul, 1505) "was the first to illustrate what were referred to as the "tier point" system ... the two lateral "tier points" (distance points)". J.V. Field, Nuncius 10(2), 1995, 509-530, abstract: "The earliest written account of the so-called "distance point method" of perspective construction is found in Viator's De artificiali perspectiva (Toul, 1505)."
CONFIRMED the "distance point" as an explicit checking device is later still http://www.noteaccess.com/Texts/Alberti/1a.htm ; https://opac.museogalileo.it/imss/resourceXsl?uri=219692 : The record's excerpt (arXiv 2210.13295: Alberti "simply says to the painter: extend one of the diagonals of a tile of the floor until it encounters the horizon ... Measure the distance") is really in that paper but is not what Alberti wrote. Alberti, De pictura Book I (Spencer trans.): "If one straight line contains the diagonal of several quadrangles described in the picture, it is an indication to me whether they are drawn correctly or not." No horizon, no measured distance, no distance point. The page's claim stands on the primary text and on Field.
CONFIRMED the "distance point" as an explicit checking device is later still https://opac.museogalileo.it/imss/resourceXsl?uri=219692 : The record's excerpt ("Leon Battista Alberti e Piero della Francesca called W the distance point", arXiv 2210.13295) is in the paper but unsupported: Alberti's Book I has no such term (noteaccess 1.htm and 1a.htm), and Field 1995 says Piero's treatise has only "a diagram like that used in the "distance point" construction", with "the accompanying text ... missing in all the Latin manuscripts", the earliest written account being Viator 1505.
CONFIRMED associated with the northern and French practitioners https://www.essentialvermeer.com/technique/perspective/about-perspective.html : The excerpt ("We do not know the precise moment at which the two lateral points received their theoretical explanation as the "point of distance."") is neutral: it supports the page's hedged "associated with", not the association itself, which rests on Pelerin (French, 1505), Vredeman de Vries (The Hague, 1604-05) and Field.
MINOR That is the self-proof Renaissance workshops used: if your diagonals all land on one point, your tile spacing was right http://www.noteaccess.com/Texts/Alberti/1a.htm ; https://pages.cs.wisc.edu/~dyer/ah336/hw/sciart-hw2.htm : The documented 15th-century self-check is Alberti's straight diagonal: "If one straight line contains the diagonal of several quadrangles described in the picture, it is an indication to me whether they are drawn correctly or not" (the Wisconsin page quotes the same passage). The "diagonals land on one point" form is the distance-point check, which the page's own History paragraph says "is later still". The record's source is a modern homework exercise, not evidence of workshop practice.
CONFIRMED if your diagonals all land on one point, your tile spacing was right. https://pages.cs.wisc.edu/~dyer/ah336/hw/sciart-hw2.htm : "If they all converge to a common point on the horizon line (called the true distance point, DP), the construction is correct." True as geometry.
CONFIRMED Real paintings deviate https://en.wikipedia.org/wiki/Perspective_(graphical) : "the majority of 15th-century works show serious errors in their geometric construction. This is true of Masaccio's Trinity fresco and of many works, including those by renowned artists like Leonardo da Vinci." Also EV: paintings "that could not be considered to be purely Albertian".
UNVERIFIABLE many masters used empirical or synthetic perspective rather than the strict construction Wikipedia search API "empirical perspective" and "synthetic perspective" (no art-history hit; control "distance point" perspective returns 3D projection); Crossref "synthetic perspective" painting; OpenAlex (daily budget spent) : No source uses these terms for Renaissance masters. The nearby, weaker statement is sourced (Perspective (graphical): "serious errors in their geometric construction").
UNVERIFIABLE artists fudge spacing for composition N1's searches; Essential Vermeer (both pages) : EV says De Hooch and Vermeer adjusted distance points "to alter the rapidity of spatial recession" and that Vredeman de Vries's edge-placed distance points may have been "to their liking": choices of viewing distance, not fudged spacing. No source found for the claim as worded.
CONFIRMED the well-attested fact that its vanishing point lies at Christ's head https://en.wikipedia.org/wiki/The_Last_Supper_(Leonardo) : "Jesus, whose turned right cheek is located at the vanishing point for all perspective lines."
CONFIRMED its single one-point vanishing point is documented to lie at Christ's head / right temple, on the horizon, at the horizontal centre https://discoveringdavinci.com/works/paintings/last-supper/composition-and-perspective.html ; https://nicofranz.art/en/leonardo-da-vinci/the-last-supper : "falls precisely at Christ's right temple"; nicofranz: "located at Jesus' right temple ... there is still the trace of a nail that Leonardo used to stretch the strings."
CONFIRMED its single one-point vanishing point is documented to lie at Christ's head / right temple https://en.wikipedia.org/wiki/Perspective_(graphical) : Note 29: "Leonardo da Vinci placed the vanishing point in his Last Supper behind Christ's other cheek."
CONFIRMED at the horizontal centre https://en.wikipedia.org/wiki/The_Last_Supper_(Leonardo) : "the face of Christ at the center of the composition". A vertical line at half width on the article's image (The_Last_Supper_-_Leonardo_Da_Vinci_-_High_Resolution_32x16.jpg, 1920 px) passes through Christ's face.
MINOR so the true vanishing point is a small region near his right temple, not a certifiable point https://discoveringdavinci.com/works/paintings/last-supper/composition-and-perspective.html : The page's own kind of source says the opposite: "falls precisely at Christ's right temple. Leonardo hammered a nail into the wall at this exact spot ... the tiny pinhole is still visible today" (nicofranz.art says the same). A point is physically marked; the region is the page's own caution about measuring photographs, not a documented fact.
UNVERIFIABLE real published analyses of the mural place the vanishing point in a small zone by his right temple, not at a single certifiable pixel, because the surface is ruined and the photo is distorted N1's searches; WebSearch "Leonardo Last Supper vanishing point nail hole Christ's temple orthogonals do not converge analysis"; webexhibits.org/arrowintheeye/arrow2.html : No published analysis found that reports a zone, or gives damage and photo distortion as its reason. Positive control: the same search found three sources locating the point (discoveringdavinci, nicofranz, webexhibits "centered upon Christ's head"), two of them at a nail hole.
UNVERIFIABLE every photograph carries lens and viewing distortion N1's searches : A general statement about photography, not sourced to the mural; not false, but nothing found that makes it a fact about this mural's photographs.
CONFIRMED the coffered ceiling, the tapestry tops along each wall, the table edge https://discoveringdavinci.com/works/paintings/last-supper/composition-and-perspective.html : "The coffered ceiling of the painted room ... The tapestries on the painted side walls". The table is visible in the Wikipedia image; its long front edge is parallel to the picture plane, only its short ends recede.
CONFIRMED Leonardo set the one point of the construction on the one figure the painting is about. https://en.wikipedia.org/wiki/The_Last_Supper_(Leonardo) : "The angles and lighting draw attention to Jesus, whose turned right cheek is located at the vanishing point".
CONFIRMED Martin Kemp, The Science of Art https://archive.org/details/scienceofartopti0000kemp : "The science of art : optical themes in western art from Brunelleschi to Seurat", 1990 (lending item; text restricted).
UNVERIFIABLE (perspective construction and the distance-point method) archive.org inside-book search (HTTP 403, restricted item); Google Books API (HTTP 429 daily quota, all four queries incl. the control); WebSearch "Martin Kemp Science of Art distance point" : What Kemp's book says on the distance point could not be read.
MINOR There Galileo guessed a parabola and the hanging chain proves it is a catenary https://en.wikipedia.org/wiki/Catenary : "It is often said that Galileo thought the curve of a hanging chain was parabolic. However, in his Two New Sciences (1638), Galileo wrote that a hanging cord is only an approximate parabola". The relates note (shown in full on the home page) repeats the story its record's source disputes.
CONFIRMED Egregium proves the round Earth cannot be laid flat without distortion https://en.wikipedia.org/wiki/Theorema_Egregium : "A consequence of the Theorema Egregium is that the Earth cannot be displayed on a map without distortion."
CONFIRMED each drops below the horizon by exactly p = h·d/(d + n·t), thinning out as 1/(d+n·t) research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : Recreated: the published copy (curl /checks/research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs, byte-identical to 60cbd1924f) prints "ok ray/plane projection equals the closed-form drop law (n=0..8)". Correct for a floor that starts at the picture plane (Z = d + n·t).
CONFIRMED neither equally spaced nor in any tidy ratio research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : Recreated: "gap0=0.3333 gap1=0.1667", "r0=0.5000 r1=0.6000". Alberti himself rejects the constant-ratio rule (spaces "superbipartienti", 2/3 each): "would err" (noteaccess 1a.htm).
CONFIRMED including the proof that the distance-point offset equals d two independent ways research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : Recreated: d = 2, 3.5, 1.4 each "dir-method = corner-line = d".
CONFIRMED the diagonal lands on the distance point to machine precision (... recomputed, not asserted) public/strata/the-floor-that-builds-itself/index.html : Recreated: the page's own formulas over widths 360/800/1400, d 0.8..6.0, five VP positions give a worst residual of 5.6e-15 tile. The residual is recomputed; the verdict word is not (see Findings).
CONFIRMED residual < 0.001 tile public/strata/the-floor-that-builds-itself/index.html : Recreated: the page script run under a DOM stub prints "✓ yes \u2014 exact" and "residual < 0.001 tile" (the dash written as its escape).
CONFIRMED Every number is recomputed in-browser from the central-projection equation and re-derived offline in research/the-floor-that-builds-itself/ public/strata/the-floor-that-builds-itself/index.html : The floor table, readouts and status call dropOf(); the Last Supper readouts come from a fixed VP (0.500, 0.430), not the projection equation.
CONFIRMED For your current eye (d=2.0, h=1.0, t=1.0) public/strata/the-floor-that-builds-itself/index.html : chkParams is written from the live d, H_EYE, T; default d = 2.0.
CONFIRMED Every figure is re-derived offline by research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : The floor figures, yes (sections 1-3). The Last Supper section re-derives only that lines drawn to a chosen point meet there, as the page says; the probe readouts in cm are not re-derived.
CONFIRMED The verifier recomputes that all reconstructed orthogonals share one point and that the point is at the horizontal centre, above mid-height. research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : Recreated: three ok lines in section 4. It uses 5 anchor points of its own, not the page's 10; true for any chosen point, which the page says.
CONFIRMED The pink line is the diagonal ... (the yellow dot) public/strata/the-floor-that-builds-itself/index.html : Diagonal stroked rgba(255,122,208); distance point filled #ffc94a.
CONFIRMED Stand close and the floor plunges; stand far and it flattens. research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : From p_n = h·d/(d+n·t): at d = 0.8 row 1 is at 0.44 of the front drop, at d = 6 at 0.86.
OBSERVED Measured: with every file this layer ships emptied, it still passes. research/verifier-independence/depends-1.json ; recreated: node verify.mjs alone in an empty directory, exit 0 : Row: "tier": "C0", "exitCode": 0, "depends": false; grading.json "opened nothing that /strata/the-floor-that-builds-itself/ ships". The file has no import and no file read.
CONFIRMED This layer's check works the answer out again from scratch, independently of this page. research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : No import, no fs, no fetch; its "page shows" values are written into the file.
OBSERVED Last verified 27 June 2026, when it was written. git log 647fcdd0353 (2026-06-27 02:31 UTC adds the layer) ; memory/log.d/2026-06-27-human-realms-wave.md:62 : Shipped in the human-realms wave of 2026-06-27; no later claims-pass record in assay/records at 60cbd1924f.
MINOR (added) Your two probes cross at "440 , 198 cm" "from the mural’s top-left, 880×460 cm", "the documented vanishing point at Christ’s head" public/strata/the-floor-that-builds-itself/index.html:663,807 ; https://thumb.wikimedia.org/wikipedia/commons/thumb/4/48/The_Last_Supper_-_Leonardo_Da_Vinci_-_High_Resolution_32x16.jpg/1920px-The_Last_Supper_-_Leonardo_Da_Vinci_-_High_Resolution_32x16.jpg : 198 cm is VP.y = 0.430 of 460 cm, a presentation choice (README: "the exact vertical fraction is a presentation choice"). On the Wikipedia article's own image (a 2:1 crop of an 880:460 wall), the top of Christ's hair is at about 0.45 of the height and his eyes at about 0.48; the 0.43 line runs through the window above his head. Even allowing 20 cm of crop, the temple is at about 0.45-0.49 (207-225 cm), not 198 cm.
MINOR (added) "documented VP region", "inside the documented VP region ✓" public/strata/the-floor-that-builds-itself/index.html:763-766,812-815 : No source documents a region or its size. The drawn ellipse has semi-axes 0.035 x 880 = 31 cm and 0.045 x 460 = 21 cm, but the readout says "inside" for any crossing under 40 cm away, so a crossing 35 cm above the point is outside the drawn region and reported inside it.
UNVERIFIABLE (added) art-historical reconstructions place the horizon (= VP height) at ~ 0.46-0.52 of the height from the top of the depicted room (verifier comment, published at /checks/) research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs:191-196; searches as for the published-analyses claim : No reconstruction is cited and none found. The figure the file then uses, 0.430, is outside its own stated range; my estimate from the Wikipedia image (about 0.47) is inside it.
CONFIRMED (added) Run it offline: node research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs re-derives the drop law from the ray/plane intersection, confirms the diagonal vanishes at offset exactly d two independent ways, and proves the spacing is neither arithmetic nor geometric. https://artwaste.land/checks/research/the-floor-that-builds-itself/verify-the-floor-that-builds-itself.mjs : Recreated: 200, 13,628 bytes, identical to 60cbd1924f; node verify.mjs: 14 ok lines, 0 FAIL, "ALL CHECKS PASSED", exit 0. "Proves" rests on one instance (d=2) for the spacing, true in general.
[declined] MINOR, self-proof-workshops: "That is the self-proof Renaissance workshops used: if your diagonals all land on one point, your tile spacing was right." Alberti's documented check (De pictura I) is a straight line through tile diagonals; the converge-on-one-point form is the distance-point check the page itself dates later. Declined under the tier C rule for MINOR lines: the bold sentence is true as geometry and the distance-point method (Viator, 1505) is still Renaissance practice; only the attribution of the check's form is loose.
[declined] MINOR, ls-vp-region: "so the true vanishing point is a small region near his right temple, not a certifiable point". The sources place it "precisely at Christ's right temple" with a nail hole reported there (discoveringdavinci.com, re-read; nicofranz.art). Declined under the tier C rule for MINOR lines: the sentence is the page's caution about measuring a damaged, photographed surface and still puts the point by the right temple, so the location a reader carries away is right.
[declined] MINOR, rel-galileo: the relates note to as-hangs-the-chain says "There Galileo guessed a parabola"; Wikipedia Catenary (re-read): "in his Two New Sciences (1638), Galileo wrote that a hanging cord is only an approximate parabola". Declined under the tier C rule for MINOR lines: Galileo did treat the chain as near-parabolic, so the note is a loose retelling, not an invented fact.
[declined] MINOR, vp-height-198cm: the mural readout prints the documented point at "440 , 198 cm" from the top-left (VP.y = 0.430, index.html:663), which on the Wikipedia image lies above Christ's head (temple about 207-225 cm) and on the page's own schematic sits at the top of the drawn head (centred at 0.47, index.html:755). Declined under the tier C rule for MINOR lines: a 10-27 cm slip on a 460 cm wall in a panel declared a reconstruction, not a measurement; the better fix (VP.y near 0.47, or no cm on the real mural) is left for a later pass.
[declined] MINOR, vp-region-test: "inside the documented VP region" is printed for any crossing under 40 cm (index.html:812-815) while the drawn ellipse is 31 x 21 cm (index.html:766), and no source documents a region. Declined under the tier C rule for MINOR lines: an overstatement of the page's own tolerance check; the crossing figure printed beside it is right.
The assay office: what a record is, and every layer re-read so far.