This cannot be built anymore with both being same (red in this case) underground belts.
https://wiki.factorio.com/File:Split%26swap2.PNG
Before 0.15 it was possible, when the placement was seeking to pair with the first clicked belt. Now it is trying to match with nearest underground belt and that turns it the wrong way.
Edit: Wait.. only now i notice the wiki one has mixed colors too? Is this still changeable?
Or this "Smart" underground placement broke some setups
Re: "Smart" underground placement broke some setups
This was never possible to build with just one type of underground belt.