Movement could be mechanically driven or happen as a result of natural effects. Image caption, Astronomical Clock, Prague, Mikulas of Kadan and Jan Sindel, 1410, Peter Scholey / Alamy Stock Photo ...

[Matthew] has written up a thorough treatment of Sunbeam movements ... century household clock. He only had the shaft and a broken original to work with, but was able to design a sturdy acrylic ...