Rolling Disk Illusion
The eight yellow points seem to be situated
on the rim of a disc rolling inside the red circle.
Click on "puzzle" check box to see the unexpected
motion each point traces in time.
Compare this applet with the applet
"Disc rolling inside a disc"
https://www.geogebra.org/m/2972175
Why/how do the two applets differ?
Why/how are the two applets similar?
Adapted from an applet by Branka Milivojevic