Link to the project:
https://snap.berkeley.edu/project?user=mr_piay&project=Isometric%20Objects%20Builer
Hi! Welcome to the forum.
Interesting project. I guess that's supposed to switch between a cube within a hole within a cube, and a hole in a cube in the corner of three walls. But I see the innermost part as a flat hexagon leaning against the corner of a hole in a cube. If I really strain I can sort of see it as a small cube, but it takes an effort. So I think there's something wrong with the shading.
Hi,
Thanks for welcoming me and for your comments.
There's nothing wrong with the shading 
Maybe it's seeing two colors (front and back) on each face that's bothering me?
Maybe, but you see what you have to see (each face with its corresponding color). Isometric drawing can be very confusing...
Right, I wasn't complaining about the project, which is very cool! Just that particular picture, which is almost the familiar optical illusion but not quite working -- because, I guess, an isometric picture isn't what you want to see for the illusion; you want to see just the visible faces. It was the particular example to which I was reacting. Peace!
Hi,
I didn't take it as a complaint (written communication is so limited and misleading...)
I guess I understand what you mean. I just was trying to say that these isometric objects are "well drawn" (only the visible faces are shown and with the right shading).
BR