i sleep at a different time, almost everyday. some mornings i have to work from 4am-9am, so sometimes i'll stay up all night, then sleep from like 9:45-3pm. or like some days i just sleep from 5am to 9am but then i take a nap from 3pm to 6pm. and some days i sleep for 12 hours straight and some days i don't sleep at all for two days straight.
i'm a weirdo. but i always kind of suspected it was a good thing that i didn't let my body tell me when to do stuff. but i was just reading wikipedia and they say otherwise. according them, sleeping during the day is pretty much worthless. i say that's hogwash. there's the wikipedia way to do it and my way to do it. and both ways work just fine.
the most important part of MY CYCLE is that you mix it up each day. throw a nap in there every couple of days. go a night without sleep from time to time. go 12 hours straight AT LEAST once a month. and coffee! don't forget to drink coffee!