Joe Jefferson sits on the front of a quadricycle being pedaled by another man in Palm Beach, Fla. Photograph by the Detroit Publishing Co., c. 1904. View full image.
Obviously it's no "commonplace tricycle." A regular trike is steered (and pulled) by one wheel in front, with two in back. This one is steered by two wheels in front with just one in back, which drives by pushing. The fourth wheel touches ground on loading and unloading, and is also used when the front section, which can be pushed like a wheelchair, is detached from the driving unit.
