Change in cycle (For is appropriate; you can use appropriate step) Top (or Top and Left, if you want diagonal move) property of the moved element:

For i=100 to 0 step -2
[element].Top = i
next i

or:

For i=100 to 0 step -2
[element].Left = [element].Left + 2
[element].Top = i
next i

If Top = 0, change direction of move:

For i=0 to 100 step 2
[element].Top = i
next i