I work from home coding, sometimes went onsite. If I'm stuck on a problem with some code which a walk or short break didn't solve, a sleep would usually solve it, hence the saying "sleep on it". I'd even sleep during the day for half an hour or a few hours just to get the answer. I've also been awake for 80hrs doing a windows server upgrade which failed horribly but I put that down to the system being hacked. Felt like a zombie, but strong tea and hard water calcium rich near London so possibly also contains unmetabolized cocaine in, played its part in being able to stay awake for that long.