Begin by clicking inside the virtual window.
The spacebar will stop and restart the ring's spinning motion.
The up and right arrow keys will zoom you inside of the ring. The down arrow key will zoom you back out.
Once inside the stone, use the spacebar to start and stop the stone's rotation. You can then place the mouse on the corner barrings to see the keel lines and ball pockets. Notice the square stone (represented by lines) and it's relation to the pocket.
Note: If the keyboard is unresponsive try clicking inside the window again.