While learning how processing commands like

• pushMatrix();

• popMatrix();

• translate(X,Y); 
  

• rotate(radians(Angle));

work. I have created simple code that simulates tank-like movement which could be used to control object in a game.

Applet and the code are available here:

http://rasco.concordia.sk/index.php?option=com_content&view=article&id=4:process&catid=7:processing&Itemid=11