WEEK FOUR
WEEK FIVE
WEEK SIX
Make the base and knock some nails to make it steady.
WEEK EIGHT
Finish the design of catapult,and add two supports to change the angle of launching.
WEEK NINE
Problem : force of the throwing arm was too big , so that the nails on the support became not steadiness .
Solution : added some nails and two another supports in front of the brace .
WEEK TEN
WEEK ELEVEN
