Where the shape comes from
A chariot seen from above: the box in the middle is the carriage, the long vertical the axle running through it, and the bars at either end the wheels. The oldest forms show both wheels; the brush kept one and squared the rest, and the simplified 车 reduced it further to four strokes. It marks vehicles and their parts: 轮 a wheel, 转 to turn, 辆 the measure word, 输, 轻, 较.