[aslkdzm]

I suggest people can also take the alternative of 6x30 mins.
The distribution of the sleeping time will be 2am, 6am, 10am, 2pm, 6pm, and 10pm. But it seems rather difficult. 2am, 6am, 2pm and 10pm are quite feasible, but for the majority, 10am and 6pm are their primetimes, so this timetable is rather hard to achieve, unless you have great flexibility in your time.