In what could be described as one small step for a robot, but a giant leap for robot-kind, a trio of humanoid machines were introduced Thursday, each with the ability to <A HREF="http://www.livescience.com/technology/050217_robot_walking.html">walk in a human-like manner.</A> The breakthroughs could change the way humanoid robots are built, and they open doors to new types of robotic prostheses.