Have you seen a crossbow made of rubber band strings? Here it is. Made by Wicky, the Reaper Crossbow uses a completely new double trigger system, which allows to hold arrows at full power, and you might use only 2 rubberband strings in the trigger one time if you want less power.
Here is the picture of the full Reaper Crossbow:
As it uses 4 strings, you can fire 4 arrows at one time! In another word, it is a repeater crossbow! The author claims that the max distance it can shoot is 200 feet without trigger, which is not bad.
Here is the list of the parts used:
Minimal Pieces Needed:
Connectors:
Blue 3d connector: 88
Purple 3d connector: 60
Yellow connector: 51
Red connector: 8
Green connector: 4
White connector: 16
Light grey connector: 10
Orange connectors: 18
Grey connectors: 2
Rods:
Green rods: 113
White rods: 130
Blue rods: 82
Yellow rods: 6
Red rods: 29
Other:
Wheels: 8
Blue spacers: 12
Grey spacers: 8
Rubberbands: 12
Recommended Pieces Needed:
Connectors:
Blue 3d connector: 88
Purple 3d connector: 60
Yellow connector: 73
Red connector: 12
Green connector: 10
White connector: 16
Light grey connector: 10
Orange connectors: 24
Grey connectors: 2
Rods:
Green rods: 117
White rods: 161
Blue rods: 94
Yellow rods: 22
Red rods: 33
Grey rods: 6
Bendy grey rod: 6
Other:
Wheels: 8
Blue spacers: 12
Grey spacers: 8
Rubberbands: 16
Small panels: 6