Long before Lego, and at the age of 14, I proved the structural potential of Meccano by building a 600mm span Warren truss bridge, that could bear my own weight.
Also, I demonstrated its analogue computing applications by making a machine comprising two gearboxes, dials, handles, etc to solve linear equations in one unknown - though this could more quickly be done on paper.
A later machine - to solve equations in two unknowns - with four gearboxes and a differential, failed after many attempts to operate due to gear and bearing friction in the days before WD40. Had things run smoothly, a little matrix algebra might have been avoided.
Richard Harvey, 6 Folkestone Road, Salisbury, Wilts, SP2 6JP