Grand design challenge

Construct mechanical device with 15 dollar budget and limited materials.

Given an initial Budget of 15 dollars, and specification and constraints of using rubber bands as the only source of mechanical power. With the only available construction materials to be foam core board, cardboard mailing tubes, and adhesives such as glue and tape. A team of 4 members must create a device that can launch bagels (up to 6) over a 6 foot wall and successfully land on a 3 by 3 by 3 cubic platform flush to the wall. Our group was able to launch all 6 bagels successfully onto the platform.