Simplify the following text for a Grade 6 native English-speaking person.
Original: The Greek mathematician Hero of Alexandria ( c. 10 â `` 70 AD ) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when .
Simplified: One of the first examples of this was built by Hero of Alexandria ( c. 10 â `` 70 AD ) . He built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums .