This amazing walking dinosaur model is a wind-up DIY wooden scale model of a full-grown Tyrannosaurus Rex. The top of the tail conceals the winding key. Remove the key and insert it into the ratchet mechanism on the dinosaur's left side, making sure the head of the left femur is clear of the opening (if you need to, flip the on/off switch to the "on" position, then spin the gear above the T-Rex's shoulders to move the leg). Flip the on/off switch to the "off" position (toward the head) and wind the mechanism half a dozen times clockwise, replacing the key to its position between the tail and body. Place the Tyrannosaurus on a smooth, flat surface, holding the automaton by the body (don't squeeze the legs together!), flip the on switch, and release. Your Tyrannosaur will stalk away, in search of its next meal, its tail swinging and jaws crunching up and down in anticipation. It's actually kind of terrifying!