This is a good test for anyone who claims to know what "obvious" means. Putting wheels on a suitcase seems obvious as soon as rubber wheels were around, and yet

This is a good test for anyone who claims to know what "obvious" means. Putting wheels on a suitcase seems obvious as soon as rubber wheels were around, and yet no one did it. There is really no good explanation for that. It IS a fact that prior to the Rollaboard, most people carried their suitcases. I've seen it argued that, "Oh, train platforms were brick, so a wheeled suitcase would be of no use!" Rubbish. There were plenty of airports and lots of air travel. Or they say, "Oh, people hired porters to carry their bags." Some did. Mainly rich people. Or maybe, "There were these wheeled carts you could rent!" Yes, those are still there. But lots of people still carried their suitcases. Obviousness has been an issue in the law for 150 years. A "teaching, suggestion, or motivation" (TSM) is often required: some reason why you would have thought it'd be a good idea to put wheels on a suitcase. Otherwise everything is obvious, since there's nothing new under the sun. Another powerful indicator of obviousness is that a technique would have been "obvious to try" for anyone skilled in the art. I hit on that for software in [1]: [1] https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2399580 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2399580