This intriguing demo will challenge your students! Help them visualize three-dimensional objects with this perplexing puzzle designed by Maine physics teacher Robert Thomas. One three-dimensional peg fits in three different-shaped holes, depending on which way you turn the peg. It could fit in either a circular, x-shaped, or square hole cut out in the board. It's not as easy as it looks! Concepts covered are appropriate for geometry, drafting, and physics classes. Includes: puzzle and full instructions.