A new book offers mathematical puzzles, such as fitting a coin through a hole that seems too small to accommodate it Things to Make and Do in the Fourth Dimension: A Mathematician's Journey through ...

Here’s what you’ll learn when you read this story: Theoretical physicists believe math shows the possibilities of a fourth dimension, but there’s no actual evidence—yet. Albert Einstein believed space ...

Last spring, mathematician Henry Segerman found a peculiar post on Facebook. It was by a programmer who had could not conjure mental images---a condition called aphantasia. Segerman immediately ...

Cosmos: Carl Sagan: The 4th Dimension In this scene from the classic “Cosmos” series, Carl Sagan imagines what happens when a three-dimensional character enters a two-dimensional world. FQXi: Taking ...