Today we saw more visual illusions in class: gelatinous ellipses and the haze illusion.

Dana also pointed out Escher for real, which realizes Escher’s paintings (both the plausible and implausible ones) physically.

For homework this week, please change the definitions of cube-vertices, noncube-vertices, and lines in gui-points.scm to make your own depth illusion (or other visual illusion). To run the program in DrScheme, choose the language “Graphical (MrEd, includes MzScheme)” under “Language”, “Choose Language”, then “PLT”. To change the eye position (viewpoint), click or drag with the left mouse button. To switch from cube-vertices to noncube-vertices, click the middle mouse button. To switch back to cube-vertices from noncube-vertices, click the right mouse button.

Please email your work to me or let me know of any problem you encounter. Have fun!