A $16,000 humanoid robot can now dance with strangers at parties. And every move it makes started as a human being in a motion capture suit. A dancer performs the routine first. Software maps each joint angle onto the robot's skeleton, which bends differently than yours, so an algorithm has to work out where the elbows and hips go to keep the character of the movement without tipping the machine over. Then the practice starts. Thousands of simulated copies of the robot rehearse the routine…