Tiny grains of naturally colored sand make up the patterns in a mandala. Mandalas can be made on glass or wood and nothing sticks the sand to the surface except gravity.
The tool used is a "chak pur." This traditional Tibetan tool is a funnel of brass with ridges. When the ridges are stroked with a stick, the vibration causes the sand to flow. Muscle and breathing control is important to achieve an even line. Since pieces can take many hours to create, it is a test of the body as well as a meditation of the mind.