Human shift work

shift work split into four hour intervals. Not working two consecutive shifts
0000-0400
0400-0800
0800-1200
1200-1600
1600-2000
2000-2400

part time would be one four hour shift in the day
full time would be two four hour shifts
over time would be three four hour shifts

or six hour intervals

0000-0600
0600-1200
1200-1800
1800-2400


Just another idea about labor efficiency.

what country works the most per day

4 hours 7 days/week = 28 hours
6 hours 7 days/week = 42 hours
6 hours 6 days/week = 36 hours