Block scheduling is a set time you will work depending on the area and you will have set days off. Senority got first pick on days off. Weekends are history most will work everyone. Nightcrews either has been or will be going to days on 2 different shifts. 4am-12:30 pm or 3 pm -11:30 pm and again senority got first pick on which shift they went to. At Sams every department will fall into 1 of 4 areas. If you work n the floor and you are full time you will either work 4-12:30 or 3-11:30 along with the nightcrew that got moved into those shifts. Parttime will work middle shifts. Made no sense moving nightcrew to the afternoon shift. Now they have go tie up 3 people to go get merchandise out of the steel to stock when they get to work.
In light of the rumor that WM could be going to implement bloch scheduling, here is a repost from @Z4VHBop-8qzc that gives a good explanation what it is