Millihertz 5: A Mechanical Replica of the Manchester 'Baby'

Millihertz 5, also known as 'Offspring', is a mechanical computer modeled after the Manchester Small-Scale Experimental Machine ('Baby'). It uses ball bearings as data elements, features an 8x8 bit RAM and an 8-bit datapath with a subtractor and accumulator. The project is currently under construction, with design documents (PDF and HTML) available online.