Office Supplies Pen Crossbow

In this instructable I will show you how to create a pen (and pretty much anything else!) launcher, using readily available office supplies.

What you need:
-Two 30 cm (12 inches) rulers. One of these needs to have a groove down the middle so the  pen doesn't fly off the worng direction.
-A fairly large elastic band. (I used one the postman dropped.)
-Some tape (I used masting tape)
-An empty drinks bottle. (I used a Lucozade bottle as it felt quite ergonomical whilst firing.) 

Step 1 Forming the main body

In this step I shall show you how to create the main frame of the crossbow.
-Firstly lay your two rulers across each other making sure the grooved one is vertical and over the top of the other one. ( A bit like a crucifix so the two sides of the vertical one aren't equal.)
-Now tape the sides together around so the groove isn't covered by tape.