This is a demo that implements various inverse kinematics (IK) algorithms.

Kinematics is the process of calculating the position in space of the end of a linked structure, given the angles of all the joints. It is easy, and there is only one solution. Inverse Kinematics does the reverse. Given the end point of the structure, what angles do the joints need to be in the achieve that end point. It can be difficult, and there are usually many or infinitely many solutions.

This process can be extremely useful in robotics. You may have a robotic arm which needs to grab an object. If the software knows where the object is in relation to the shoulder, it simply needs the calculate the angles of the joints to reach it.

I've selected a Greek folklore hero Karagiozi to show the animation known for his long arm (5 bones). Karagiozis along with other characters are characters in a special kind of theater; that of Shadow-puppet theater.