[tomp]

However, that is not the purpose of the patents.

You can't patent an idea, you can only patent an implementation of it. E.g., I can't patent a flying carpet until I actually know how to make it and prove that I can (by making it or being very specific in technical instructions on how to make it).

An patent is obvious if you can explain the idea, i.e. what you want the machine to do, to a graduate engineer/scientist, and have him implement it. As for the famous doubly-linked list patent: if I tell a programmer: "I have a number of items {A, B, C, D, E}, and sometimes I need to access them in the [A -> B -> C -> D -> E] sequence, and othertimes I need to access them in the [B -> C -> E -> A -> D] sequence. Make an efficient/working implementation of it!", then any programmer could come up with the doubly-linked list implementation. Ergo, it is obvious.