A sand writing pendulum is a device that creates mesmerizing and intricate geometric patterns by releasing a thin stream of sand onto a surface as it swings. The resulting artwork is temporary, reflecting the principles of physics and harmonic motion. 

Components

The pendulum: A container, such as a funnel or a spherical weight, is filled with sand. A small hole at the bottom allows the sand to trickle out.

The suspension: The pendulum is hung from a frame by a single cord or by multiple strings. This allows it to swing freely in two dimensions.

The base: A flat, shallow box or table filled with a layer of fine sand is placed underneath the pendulum. The contrast of the pattern traced by the moving sand is often highlighted by using dark-colored sand in the base.