I need to Create 7Monsters within 10 seconds !!! but...but I don't have the logic

I want to spawn 7 monsters in 10 seconds but in increasing numbers, like "1.1.0.1.0.2.0.0.0.2" or "1.0.0.1.0.2.1.0.0.2". Instead of 7 random ones, because in random case 7 monsters may appear in the first few seconds. Instead of spawning all 7 monsters in the 10th second.

There is probably a better solution, but it seems to work: