Rubber-Band Bow and Arrow

I was bored on a Saturday afternoon and with an engineer friend. We decided to have a contest to see who could design and build the best printable bow and arrow, using the following constraints:

One 100mm x 100mm panel of parts
No more than 2 rubber bands
No adhesive
"Reasonable" print time (under 1.5 hours)
"Reasonable" design time (under 1.5 hours)

This was the my entry. The picture is of the first revision, which had a few issues (pins were too small to print cleanly, holes were not