Stack it Up

Your task in this fun physics game is to stack blocks on the platforms so that they reach the target height and prevent them from getting knocked over by flying balls. Every two levels you can chose from 3 upgrades for your blocks. Use YOUR MOUSE to select a block from the sidebar, and then put it on the platform. Once the tower reached a height of a horizontal line (or you're out of building points), click 'OK', and hope that it will stand for 10-20 seconds. Good luck!