1. The Purple Cobra Built by Ben Graham and Preston Garland

2. The Purple Cobra
The design of the device is broken into three parts. The ball begins with a series of slanted ramps which lead into a ribbed stretch of tubing, taking the coaster on a horizontal, declined loop which exits onto a slanted pegboard. After bouncing down the pegboard, the ball will finally land in the cup at the bottom.

3. Stored Energy throughout roller Coaster

4. Design/construction issues
The original design called for a track built of mostly tubing and pipes, which later had to be reduced considerable do to the lack of malleability of the pipe.
The original design for the slanted ramps call for several pieces of slowly declining, u-shaped pieces of piping, which was later found impossible to attach to supporting board.
Marbles have become a rare item in toy stores.

5. Conclusion
The roller coaster falls just short of the 15 second requirement, making the project, for the most part, successful.
One of the difficulties we encountered was the large number of calculations required due to the large number of different and variable forces throughout the ramps and pegboard.
If given another chance, we would have tested materials for thoroughly beforehand and had a precise design/model before buying materials, due to problems encountered in the building process.