I have had segmented sleep all my life. I can not remember ever sleeping all night unless given a sedative. Currently thanks to some meds I take, I go to bed around 930, wake up around 11 or 1130, putz around reading or on the computer until around 1 am, then sleep until about 3, then wake up and putz around reading until mrAru and I have breakfast and I take my meds at 5 am, then back to sleep at about 6, sleep until 9 or so, awake until after I take my meds at 1 pm, sleep until about 3 pm, then awake until 930, lather rinse repeat.
Makes road trips and such interesting. I tend to pull into rest areas and sleep in the car when my nap attacks hit.
Back before I had to take meds that knock me out, I would go to bed about 11, wake up at about 1, putz around for a couple hours and crash again around 3, wake up at 5 to do breakfast with mrAru, back to bed about 6 and sleep til 8 or 9. I got in the habit of waking up for breakfast with whomever I was living with back when I lived with a physically abusive man - he wanted me to make his breakfast and make sure his suit was ready/brushed and his shirt was freshly ironed. Since it was no bother to wake up and do breakfast with mrAru, I keep in the habit of doing so - it is sociable to have breakfast with him.