Algodoo

holy hell that's good!

For loops are pretty simple, you have to do

for(5, (x)=>{
spawn code here
})

my advice is, first write the for structure like this:

for(5, (x)=>{})

and THEN put the spawn code in between the brackets. that way you don't forget a parentheses or whatever

also try using less, but bigger radius spawned circles, it may halp with performance if you can manage to get them out of the combustion chamber