Ah, well, in each room there is generally only a short sequence. I made it so I could, in theory, have up to 15 blocks appear in one room, but most rooms only have 4-6. There is one with 8, but the 8 sort of build a bridge for you.
This is the second area of the game, so I didn't get too evil with these. Hehe. You still have to have timing to pass these, but I think it's fair.