Found this interesting

[scott]

http://laughingsquid.com/optical-illusi ... ng-circle/

[Tarsier79]

It is interesting. Not really an optical illusion though, is it. Those points on the circle will move in a straight line providing the geometry is correct.

[scott]

^yep

[rlortie]

Interesting!

Sheds new light on old things! First thing that comes to my mind is MT 137, is this possibly the discerning thing we are supposed to be looking for?

Ralph

[Unbalanced]

Thanks for sharing this Scott. It was interesting to me to see that half the balls (4 of 8) were needed to begin to see rotation.

I would like to see this demo with the orange circle rotating (CW and CCW) as well but I can't turn my iPad that fast without a turntable. Especially where it shows just one then two balls in motion.

[Unbalanced]

Now that I've watched it four more times, I see the illusion of rotation starts with three balls.

If we rotate the screen at the same speed so as to keep the white "circle" in one place in relation to the orange circle, for example; on one side centered on the equator, weight paths for a new configuration spring to mind.

[Grimer]

Reminds me of pathfinder's stuff.

[path_finder]

Many thanks to Scott for the refresh of this fundamental geometrical property.
http://www.besslerwheel.com/forum/viewt ... 3618#73618
http://www.besslerwheel.com/forum/viewt ... 8518#88518
http://www.besslerwheel.com/forum/viewt ... 8590#88590