Things You'll Need
Instructions
Stack two bricks one on top of the other with their widest face flat on the ground. Place the third brick at an angle between the ground and the stack of bricks. It should lean against the stack at a 45 degree angle.
Bend one edge of the cardboard lengthwise to develop a short section measuring five inches from the entire length of the cardboard. This edge will rest on top of the stack of bricks, providing a flat area on top of the ramp's transition. Place the short section on the stack of bricks so that the rest of the cardboard leads down over the angled brick. Use duct tape to secure this flat top to the stack of bricks.
Use duct tape to fasten the middle section of the cardboard to the angled brick behind it. This will develop a nice transition, providing you with a realistic quarter-pipe ramp design.