He is doing a special exercise to strengthen his extensor carpi radialis brevis.

The extensor carpi radialis longus is a part of the arm muscles and helps in the movement of the wrist.

Ogura Hyakunin Isshu is one of the classical literatures of Japan.

This 立方半八面體 is one of the shapes in geometry.

The great icosihemidodecahedron is a cube with a very complex shape.

This is a model of a great icosahemidodecahedron.