Occasionally (sometimes often, sometimes rarely) I try to do my best to answer some question on stackoverflow.
Recently I have answered this question but at first I had interpreted badly the OP request: in fact my first proposed solution told him to use grep to eliminate the lines containing final asterisk. But the user wanted the asterisk to be ignored, not the line to be deleted. So I fixed my answer to use sed to delete the asterisk and let diff make its work.
The edit has timestamp 2013-04-23 13:28:19Z.
Soon after I posted it, I saw another answer which proposed the same "double pipe" solution I gave but with the correct sed. Its timestamp was 2013-04-23 13:28:50Z, i.e. it came after the fix of my answer; in the same time it cites my previous wrong answer, so it was "built" on the shoulder of it (the one with the grep instead of sed).
That was interesting and made me think about a reason to be strongly against some kind of usage of patents (and maybe the whole patent industry), and how these can stop indeed independent innovation and ideas. Patent advocates state exactly the opposite, but it's of course a matter of defending their interests (and/or protegees)... a matter of money and not of innovation, progress, expanding human knowledge and so on.
The point is this: we proposed the right sed-solution independently. (He credited me just for the structure of the command line, i.e. the way the sed command is invoked in order to obtain the diff). Saying it differently, the functional part of the answer (the sed trick) was "produced" independently by each others.
This shows that having the same problem to be solved, having similar knowledges, similar shared informations and similar set of tools can make two minds to propose solutions that are similar if not identical.
That's why patents to "protect" intellectual properties are a very dangerous lie and stop innovation, giving the key to it in the hand of "who came first" in order to make money, prohibiting other minds to arrive to similar solutions independently.
The simpler is the "object" of the patent, the higher the probability two or more people produce the same solution. So that allowing patents can prevent others from using shared, common, widely available human knowledge to reach any result, lock the consumers of a solution to one solution provider (for a long time) and so promote differences, cutting the less rich out from the game and make it possible price control to maximize earning despite the intrinsic value of the "object" (when applicable), in detriment of the consumers.