Henry Segerman, a British American mathematician and mathematical artist at Oklahoma State University, has invented a puzzle to help explain the Earth's annual trip around the sun: Continental Drift, a 3-D sliding puzzle that made its debut earlier this year. The underlying geometric concept is holonomy: When you travel a loop on a curved surface and return to the starting point, you arrive somewhat turned around, rotated, perhaps by 180 degrees. It's just one of Segerman's inventions that help visualize mathematics. A few years ago, Dr. Segerman demonstrated Extensors: a construction kit for making extending mechanisms from scissor-like hinged parts. Sabetta Matsumoto, an associate professor in the School of Physics, applied mathematician, and Dr. Segerman’s partner, gave input into the contraption’s development and came up with the name Extensor. Between them, math is “a pretty common conversation,” said Matsumoto, who was featured in a 2019 New York Times story about her project to investigate the mathematics and mechanics of knitting. (This story also appears in Yahoo! News.)