I’m a bit chagrinned to admit that having been mired in details I failed to see the obvious.
In standard paper sizes (ISO 216) and pen-point sizes (ISO 128 &c), the square root of two is used as the interval between sizes, and between the short and long sides in the case of paper. This makes good sense for the purposes of mechanical enlargement or reduction. If you draw or write something with a #2 pen (0… Read the rest