This is a 2 column layout (12/6=2)
col-2
col-2
col-2
col-2
col-2
col-2
This is a 4 column layout (12/4=3)
col-3
col-3
col-3
col-3
This is a 3 column layout (12/3=4)
col-4
col-4
col-4
This is a 2 column layout (12/6=2)
col-4
col-4