Marbelous, 3114 31 bytes
..@0
..6C..@1
@0/\..6F6F@0
....4C@0/\@1\4C
Marbelous is a language based on marble machines
@n
(n
from0
toZ
) is a portal which teleport the marble to another portal with the same value00
-FF
initiate a marble with this value/\
create a duplicate passing marble to it's left and right..
is a noop- marbles going out of the machine from the bottom are implicitly outputed
-17 bytes thanks to DLosc