Used in this model mechanism for reciprocating motion have been well illustrated in book "The Lego Mindstorms EV3 Idea Book" on page 47.
Free end of vertical axle is for supply power from power engine.
The human leg, in the general meaning, is the entire lower limb of the human body, including the foot, thigh and even the hip or gluteal region. However, the definition in human anatomy refers only to the section of the lower limb extending from the knee to the ankle. Legs are used for standing, and all forms of locomotion including recreational such as dancing, and constitute a significant portion of a person's mass.
Morse code is a method of transmitting text information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment. It is named for Samuel F. B. Morse, an inventor of the telegraph.