'fill array
mx,my = 30
> y, 1..my
  > x, 1..mx
    a[x,y] = #.rnd(20)+1
  <
<
'scan array
> y, 1..my
  > x, 1..mx
    #.output("x=",x,", y=",y, ", a=",a[x,y])
    << a[x,y] = 20
  <
  << x!>mx
<