This is the word selection window. Each word is some string in the digits 1,2,3. Each of the 10 red buttons represents a word using an icon. The icon is a hexagonal path in the plane. The path is made by dividing the three kinds of edges in the hexagonal grid into types depending on the direction of the edge, and then following these edges according to the digits in the word. The fact that the paths are all closed indicates that the words we are considering are all stable: They describe periodic billiard paths in open sets of triangles. If there are more than 10 possible words you can use the arrow keys to cycle through the list. If you click on one of the red buttons you focus the applet on that word.