Hooke's joint

[Arm out the window]

Maybe Hooke was smoking one when he came up with the concept, I'm not sure.

All I remember about it from principles of flight lessons was that the guy giving the talk had 2 rulers held together with a bit of a coning angle, then he tilted them forwards and said "there you go, like that...Hooke's joint effect!"

Now I never understood that, funnily enough...would anyone like to have a go at explaining what it is and how it works in layman's terms, if possible?