Sprinkle sand into the container to create colorful art. The color of the sand is
selected by clicking on one of the color patches at the top. The top left
button sets sand removal mode which persists until a color patch is selected.
In this mode, all sand directly above the mouse cursor while clicked is removed.
The whole process can be restarted by clicking on the top-middle button.
You can email the picture to someone by pressing the top-right button.