My greatest Lego triumph was the creation of a miniature monorail that required pushing the car down a little Lego track. YouTube user sumthinelse5790 (real name Max Shepherd) has blown my childhood creation out of the water with a Lego robotic arm.
Admittedly, this, but it does show off a high level of sophistication.
Shepherd went in with the lofty goal of accurately mimicking the full range of motion of a normal human arm and hand.
The result is pretty successful. Lego pneumatics power the complex hand and wrist movements. The hand can even spread its fingers out to the sides. Each digit is independently controlled.
The Lego arm is designed as an above-the-elbow prosthesis, but don't expect to see it out in the wild anytime soon. The model can't lift more than a couple pounds and it requires a cluster of switches and joysticks, as well as an air compressor or hand pumps, to operate.
Check out the video below to see Shepherd's creation in action.