thread I am not advocating this, but . . .
when she was not working, my mother used to divide a fortnight into 21 days.

I would get 4 hours' sleep, followed by 12 hours awake, rinse and repeat. You need good curtains, but I just would not ever sleep for more than 4 hours, whatever happened, but it turned out that i would do it more often than expected, so I had 3 'days' in every 2 actual days.

This is all pre-school age mind, and I went to school at 3, so . . .
permalink That is some very dedicated parenting.
My friend's retraining to be a nurse, with the intention that she'll be able to be around more at the times when they need her and sleeping when they're at school... I don't know how that'll pan out!