for loop with more items

[RWS]

Hi there. I'm doing some experiments with Nim. Can anyone explain how this code:
    
    
    for x, y  in [0..10, 0..10]:
      echo(x)
      echo(y)
    
    
    Run

gives this output:

0 (a: 0, b: 10) 1 (a: 0, b: 10)

and is there a way to work this 2 or more items in a for loop? Thx