This variant has a shorter core, 5 hours or less, which usually consists of 3 sleep cycles. One of the most popular proposed forms is 5h + 30m. Similarly to Siesta, the 3-cycle core is extended to 5 hours, which allows to get more light sleep and REM for sustaining E1-shortened. The nap is extended to 30 minutes, which further increases total sleep time and should make the schedule more sustainable.
This schedule is more difficult than the standard one, but might be possible for those with a lower sleep needs (~6-7h on mono).
