In this small demo I've made a 'tentacle' object that uses inverse kinematics. For me this was a way to get a better understanding of the princeples of kinematics and learn more about the ofxVectorMath addon. You can drag your mouse, and the tentacle fill follow.
Each segment will try to rotate towards the end of the previous one (or the mouse pointer in case of the fisrt segment). If it's out of reach, the segment will move to connect to that point.
This for sure isn't groundbreaking stuff, but if you like, you can download the program and source code.