Making a trebuchet (although the size was fairly smaller than the actual one) was not an easy task. Three of us worked on this project and it took us approximately three to four hours daily for approximately three weeks. First, we made the base and attached the pulley and the handle. Then we made the crates and the basket. After finishing we decided to see if the trebuchet really worked. The crates that were filled with tiny stones did not have a force enough to throw the stone far away. So instead of the tiny stones, we decided to fill the crates with lead. We also made some changes on the basket. Initially, the basket was hanging from a rope. Because it wasn't stiff, the basket would turn around and would not be able to throw the stone at the aimed point. Therefore, instead of the rope we changed it to a thin iron string that kept the basket from moving. After several trials, we were able to throw the stone as we wanted.
Mariano Taccola and His Book De Ingeneis by Frank D Prager and Gustina Scaglia (The MIT Press Cambridge Massachusetts, and London England, 1972)