Second general block.     A empty default container (1 col by default) follows

This is the 4th block.   Actually is just the third gb.  

An empty 3 col container follows

This is the 6th block.

Following this is a default (cols=1) container but this one has 2 blocks

Following this is a 3 col container block whose 1st and 3rd slots are filled.

Note what happens when previewed -- does the missing slot keep its position?