I have a lot of friends who come from electrical / physical / mechanical engineering background, and are curious about what is "OOP" all about. They all know Matlab quite well, so they do have basic programming background; but they have a very hard time grasping a complex type system which can benefit from the concepts OOP introduces.

Can anyone propose a way I can try to explain it to them? I'm just not familiar with Matlab myself, so I'm having troubles finding parallels. I think using simple examples like shapes or animals is a bit too abstract for those engineers. So far I've tried using a Matrix interface vs array-based / sparse / whatever implementations, but that didn't work so well, probably because different matrix types are already well-supported in Matlab.