<Source: Internet.>
E.g.
... = empty space
sss = storage activities area
111 = production activity 1 area
222 = production activity 2 area
333 = production activity 3 area
ssssssssss...........................
ssssssssss...........................
ssssssssss...........................
1111122222223333333333333
1111122222223333333333333
.........2222222......................