Complex sentence: A gear train is a set of wheels that engage through teeth along their various circumferences, and are found in the Antikythera mechanism of Greece and the South Pointing Chariot of China.
Split into simpler sentences: A gear train is a set of wheels that engage through teeth along their various circumferences. The use of gear trains can be traced back to the Antikythera mechanism of Greece and the South Pointing Chariot of China.