2d gas simulation interactive

It is possible to move balls with mouse. Clicked ball will get velocity of pointer.

It is part of the project: http://physics-toolbox.tripod.com/
Author: http://simulations.narod.ru/
2d gas simulation interactive. Program starts with window of parameters: box sizes masses velocities etc. Then simulation starts. It is possible to move balls with mouse clicking the ball. Clicked ball will get velocity of pointer. Also other controls: accelerate, random velocities etc. It is possible to return to window of parameters. Simulation window is elastic and it is possible to stretch it to fill all screen size. See move of it here:
http://www.youtube.com/watch?v=PDRt5BQ4UUw

Unzip and run rum_me.m in Matlab.

Thanks to Kotkin G. and Cherkasskiy V. for initial not intaractive simple code.