We starting playing with the bug to find out how we did it and this is what we have found:
- Set up as showing in figure 1, can be any liquid.
- Extent the setup with some extra pipe and one extra underground pipe, see figure 2.
- Set up a upgrade planer to include underground pipe to pipe
- The underground pipe marked in figure 2 can be marked to be upgraded, the bots will replace it with the pipe marked in firgure 3.
- The two pipes are now connected with the underground pipe; done any other way will cause the undergrounds not to connect.