Backflow in blocks

[Lankreijer]

I would like to create a subsystem which looks like:

---------------
>| |>
| |
<| |<
---------------

Sorry that this drawing is not very clear, but I would like to have an input and an output on both sides.

Can you help me with this?

 

[Phaneas]

Sorry, I tried that, too. But that is not possible

Best Regards
Phaneas

 

[Lankreijer]

I did find a sort of solution:
Two blocks above each oter. The upper one normal and the bottom one fliped. Connect the middle two ports and the backflow is visualised.