Low density gas is blue and transparent and high density gas is red and opaque in the display. Initially the gas is smooth, but over time filaments develop and regions of particularly high density form at the intersections of the filaments. In between the filaments are large voids with little visible matter. Notice that structure formation continues right up to the present time.

This simulation uses a mixture of hot and cold dark matter. Here are further details of the calculation. Usage: Click "Play" to begin. Click "Stop" to pause. "Step" moves forward one frame, and "Back" moves backwards one frame. "Home" returns to the beginning.