Merry Go Round Painting (Two Panel View)
Dan Anderson pointed out this great puzzler from Tom and Ray Magliozzi, or Click and Clack, the Tappit Brothers from Car Talk. Original puzzle page: http://www.cartalk.com/content/painting-carousel-0 The problem is on the first slide, an exploration on the second and a diagram of the Merry Go Round in the puzzle on the last. This copy is a modification of John Golden's adaptation at https://www.geogebra.org/material/show/id/224259 The minor modification involve changing to a two panels view, and instead of a slider, forward and backward buttons to control the changing scene is used.
More GeoGebra at bit.ly/mh-ggb