A simple WebGL pendulum swings in blue against a white canvas, anchored at a fixed point and connected by a line to a circular bob. The simulation runs continuously, rotating the bob and wire around the anchor using a shader-based rotation matrix. Users can click buttons to increase or decrease the angular velocity, speeding up or slowing down the swing. Rendered with the WebGL API, the example draws points, a triangle fan for the bob, and lines via raw vertex buffers and custom shaders.