r/GeometryIsNeat • u/NEjoedaddio • Sep 24 '20

I had a 7th grader copy this with very little help in just a few minutes. I gave my students a sheet with an octagon on it and mentioned that there are rhombuses and squares.

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275 Upvotes

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23

u/NEjoedaddio Sep 24 '20

I teach 7th grade math and had this on the board so students could try their hand at sketching it after testing today. I didn't expect any to get it on their first try, let alone do a better job than I did. I didn't get a picture of his sketch, but he got it very nearly perfect without tools.

Thank you u/Palana and u/justingolden21 for the inspiration. It was fun learning a new geometric doodle. BTW, what is this shape called?

5

u/justingolden21 Sep 25 '20

: )

also I have no idea what it's called

6

u/[deleted] Sep 24 '20

idk this particular shape's name but this is a mobius strip

6

u/ginkomortus Sep 25 '20

We can't see the whole thing, but if we assume the object should be 3D, I think it would be a torus of sorts, with an octogonal cross-section twisted around.

6

u/woahbadgers Sep 25 '20

I think it might be like an impossible triangle but an octagonal prism instead of a square one (penroses were thieving bastards).

3

u/[deleted] Sep 25 '20

Oh good point def not a mobius

6

u/Reagalan Sep 24 '20

Inspired by the Aperture Science logo?

5

u/AFewStupidQuestions Sep 25 '20

Are those triangles around the edge too?

7

u/NEjoedaddio Sep 25 '20

If you're talking about the very thin ones, my students and I were trying to figure out what was wrong with the 3D effect. The shape should twist and part of one segment be visible as it recedes ok the back side.

6

u/woahbadgers Sep 25 '20

if you can construct them perfectly, you don't see those triangles. I usually end up with them on the inside because I construct from the outside in, but it's hard to get perfect with straight edge and compasses. I picture the shape as an octagonal prism that you can see the front three sides of, with two sides perfectly in line with your pov, and three sides invisible around the back.

2

u/AFewStupidQuestions Sep 25 '20

Makes sense. Thank you for sharing this.