The shift patterns are based on a 10 day cycle... core shift is shown as 1st one others are examples but not all of what could be worked if not working nights.
1 2 3 4 5 6 7 8 9 10
m m a a n n s o o o
m m a a o m m o o o
m m a a a a o o o o
m m a a m m o o o o
hope this helps