You are the vailiant one who has been chosen to save the roads. You are the driver of a massive trolley, carrying blocks built to stop the pistons. At every road, the pistons are coming down with a known force. Your job is to put blocks under the pistons that have a greater strength than the force of the piston coming down(You can see the current force in the Force area on the left of the screen).
Your friends are busily building the blocks, they appear in a chute on the left side of the road. Unfortunatly, they are working very rapidly, so they cannot give you the strongest blocks all the time. The blocks will have a resistive strength of 1-10.
