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@mrflip
Last active December 14, 2025 19:39
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Ancient Greek Geometry walkthrough / answers / cheats

Solutions for Ancient Greek Geometry (https://sciencevsmagic.net/geo)

Most solutions taken from the about thread. See the comments below for more additions since my last check-in.

Polygons

Circle Packs

Circumscribed Polygons

Non-Constructible Figures

Abuse of floating-point math can make the widget approve non-constructible polygons (polygons with edge count 7, 9, 11, 13, 14, 18, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 33, 35, ..., which cannot be precisely constructed using straightedge and compass):

@ILoveMath62
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ILoveMath62 commented Nov 23, 2025

9-move Circle Pack 3 alternative

@ILoveMath62
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ILoveMath62 commented Nov 23, 2025

If you take the 11-move pentagon and remove the pentagon itself, you get the angle for the triacontagon. Using the star trick, this is the only possible 37-move triacontagon. (I don't know why it takes so long to render)

@ILoveMath62
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ILoveMath62 commented Nov 23, 2025

If you take the 35-move hendecagon (the one I would've shared if I'd never made the 28-move one) and bisect, you get a 46 move icosidigon. I can't share it though because it glitched. This is the link to it before it glitched. Finish the last move to make it.

@ILoveMath62
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ILoveMath62 commented Nov 23, 2025

From the 75-move nonadecagon, (enneadecagon) I decided to make different circles to get the points required, and actually get the points not on the x-axis, and form the parallel line needed to make the circle required, and use the star trick +several more to get 56 moves.
Edit: I managed to star with the starting 8π/19 angle to save 2 moves from the nonadecagon. New nonadecagon
Edit 2: I made the parallel line in a different way to save 7 moves.

@ILoveMath62
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ILoveMath62 commented Nov 26, 2025

Circle Pack 19 in 36 moves instead of 37. Circle Pack 15 in 41 moves. If the Circle Pack 15 had each inner circle r=1, the big circle would have r=1+sqrt(6+2/sqrt(5)+4sqrt(1+2/sqrt(5))), or this.

@ILoveMath62
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ILoveMath62 commented Nov 27, 2025

I took a different tangent for the icosiheptagon to make it in 49 moves.

@ILoveMath62
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ILoveMath62 commented Nov 27, 2025

Sharing decagon since the one shared here has an incorrect move. Dodecagon alternative (also 17 moves)

@ILoveMath62
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This probably explains why the widget sometimes glitches while rendering shapes. The 24-gon looks like this if you change line 28L33 into 28L10. This will load slowly.

@ILoveMath62
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ILoveMath62 commented Nov 27, 2025

I don’t know why these approximations even exist. 19-gon A 19-gon B nonagon

@ILoveMath62
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I removed 3 unnecessary moves from the icosanonagon to get 57 moves.

@ILoveMath62
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ILoveMath62 commented Nov 30, 2025

Hi, interesting stuff, I am here, I can't look at all of this right now, but I'll look into it I'm the near future, I'm still interested, and wondering how to neusis construct a 11-gon...

Maybe we should make a discord for all of this? It might make discussions easier...

(My discord is the same as my GitHub)

Eddy119, this reply you made has a grammar error. "look into it I'm the" Change I'm to in, please.

@ILoveMath62
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If you star with twice the starting angle of the heptadecagon, you can get 38 moves.

@ILoveMath62
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ILoveMath62 commented Nov 30, 2025

I managed to remove an unnecessary move on the 41-gon to get 62 moves. (I don’t know why it counts. This can be done)

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ILoveMath62 commented Dec 6, 2025

13-gon by taking the tangent in 30 moves:
13-gon
49-gon by taking the tangent:
49-gon
50-gon from 25-gon:
50-gon

@ILoveMath62
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ILoveMath62 commented Dec 6, 2025

26-gon in 43 moves 18-gon in 33 moves 23-gon in 46 moves 11-gon in 27 moves

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The 16-gon had 23 moves reported possible, finally I constructed it from the octagon.

@ILoveMath62
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I don’t know why it didn’t work by using the nonagon, so this is my 36-gon.

@Ian-Zander
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Ilovemath, your 50-gon link goes to the 49-gon

@ILoveMath62
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ILoveMath62 commented Dec 8, 2025

40-gon in 49 moves. This will load very slowly. (Not in-origin.)

@ILoveMath62
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So I tried to make the 51-gon from the heptadecagon. Floating point made a 2-gon. I [censored] hate when that happens.

@ILoveMath62
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46-gon in 70 moves:
46-gon

@ILoveMath62
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@ILoveMath62
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Dodecagon in 16 moves.

@ILoveMath62
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(in-origin?) Decagon in 16 moves.

@ILoveMath62
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ILoveMath62 commented Dec 13, 2025

I accidentally deleted a previous comment.
18-gon
35-gon
37-gon
39-gon
41-gon
43-gon*
45-gon
46-gon
47-gon
53-gon
54-gon

@ILoveMath62
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ILoveMath62 commented Dec 13, 2025

Nonagon in 19 moves.

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(unincluded) Square Pack 5 in 27 moves

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I had to use the old 18-gon to make this. 36-gon in 55 moves

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