Quadricycle

Quadricycle (also spelled quadracycle or quadrocycle) is a four-wheeled vehicle. The most common layout is when the wheels are placed at the angles of a rectangle. The alternative layout is when wheels are placed at the angles of a rhombus (or, more generally, at the angles of a geometric kite). The rhombus layout is not very convenient, because such vehicles are less stable and leave three tracks instead of two. Quadricycles were one solution to the problem of low-speed stability in early cycles, typically multi-seat models (as seen in the picture). Both tandem (in line, as depicted) and sociable (side-by-side) seating configurations were used. The first experimental steam cars were sometimes called steam quadricycles, and a few very early internal combustion cars were called motor quadricycles. The terms automobile and car rapidly became universal, supplanting this usage.