How to use ? - Catapult
Step 1
Cut the skewer with a pair of scissors to form 2 bars:
- 1 bar about 8cm long
- 1 bar about 10cm long (i.e. 2cm longer)
Step 2
With a hammer, push the smallest bar in one of the clothespins in the center of the spring (small metal circle).
Do the same with the other end of the bar by pressing it into a second clothespin.
If the skewer is a bit thick narrow it a bit with a box cutter. If it is too fine, glue it in place. 
Step 3
Pinch the second bar with the clothespins already fixed to the first bar.
The bar must fit in the small circle at the back. It comes out a little bit on both sides.
Step 4
With the two other clothespins, pinch (on the narrow side) the two clothespins already fixed with bars.
Check the stability of the construction.
Step 5
Attach the clothespegs together with two small rubber bands.
Step 6
Pass the big rubber band around the clothes-pegs linked with bars, just above the top bar (where there is a slot for part of the metal spring).
Twist a bit the large rubber band.
Pass a spoon through the center of the rubber band, and then between the two bars.
Adjust the position of the spoon so it can easily tip over backwards and is stopped sharply against the top bar when released.
Step 7
Here is a side view to understand better where the locations of the various elements are.
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