Geometry Paradox Puzzle
Here is the “vanishing area” puzzle explanation I promised. It turns out to be part of a whole course-of-study at the university level. The key ingredient is the natural assumption that the simple figures and dividing lines fit together, as expected, with no gaps.
The new rendition of this puzzle is cleverly made of corrugated cardboard, cut with a knife ... so you sort of excuse the perceived gaps and imperfections in fit. That allows this one to progress beyond the first stage, which results in a new grouping of the figures that now seem totally fill the open area. However, there are still long, thin gaps between the cardboard figures that make it possible to insert yet another figure. Clever.
