Marble solitaire is played on a board with a grid of 33 holes. At the start of the game there are marbles in every hole except for the central hole.
Marbles can jump vertically or horizontally over a neighbouring marble and into an empty hole on the other side. The marble that was jumped over is then removed:
You can select a marble by clicking or tapping it, or by using the tab key. You can then jump by clicking or tapping an empty hole, or by using the arrow keys.
The aim of the game is to remove all of the marbles except for one.