And interactive simulation of an incompressible flow, which the user can push around and inject color into.

Available on Shadertoy. (Not suitable for mobile)

The implementation is more or less your standard grid based solution for incompressible inviscid flow, with the exception of the pressure term being solved in one single pass instead of many. This approach was chosen due to Shadertoy only allowing for a limited number of passes to be executed each frame.

The simulation was developed using my own Shadertoy development environment DemoRun.