There is a variety of historical forms of this character. According to Uncle Hanzi, they stand for “a person in profile”. It’s not clear whether it’s an arm or a leg sticking out. Ponte Ryūrui says that 人 “is a pictograph of the left-hand side profile of a standing person”. He also notes that in certain forms
the shape of the character 人 emphasises two parts of the human body, the elbow and the shin. Additionally, the entire posture of the body is curved (in some forms it even seems to be cringed), further emphasised by the bent back and knees.The modern form of 人, however, is best thought of as a pictogram of a person (standing on two legs) en face. Why “best”, we’ll see tomorrow.