Integer loops are constructed by telling a number to drive the loop. Try this example to count from 1 to 20:
1 to: 20 do: [:x | x printNl ] !
There's also a way to count up by more than one:
1 to: 20 by: 2 do: [:x | x printNl ] !
Finally, counting down is done with a negative step:
20 to: 1 by: -1 do: [:x | x printNl ] !
