There's something very seductive about the movement of fluids. Whether it's water in a stream, or smoke rising from a fire the patterns are similar and beautiful in their complexity. We've been doing some experimentation and managed to create a fully functional simulation of a wind tunnel. You can choose different vehicles and see how they perform or use the brush and draw your own streamlined shape. To do this we've had to solve the Navier-Stokes equation which until recently was the preserve of dedicated high power computers. These days however, you can try it yourself if you've got a recent multi-processor PC. Even if your PC is getting on a bit you can still see the video. Go on, give it a go.