flexagon

[ flek-suh-gon, -guh n ]
/ ˈflɛk səˌgɒn, -gən /

noun

a three-dimensional figure having polygonal faces that is constructed from a folded sheet of paper in such a way that different faces are exposed when the figure is flexed along its folds.

Origin of flexagon

flex1 + -agon (as in hexagon, pentagon, etc.)