I'm confused by the blinking ellipses - what exactly are they?
Bunches of retractable bridges.
Do you have any ASCII screenshots as well?
(http://s8.hostingkartinok.com/uploads/images/2016/07/bd4eb50b15fad1a3a1b53e60be3cf596.png)
Was there pressure from above the magma spout?
No. Just 522 pumps and that's all.
I know about the paint image graph, but what other tools you use for designating? Quickffort?
CraftWare: https://craftunique.com/craftware
I download 3D model, create slices like this:
(http://s8.hostingkartinok.com/uploads/images/2016/08/a2ccb8822bbe3497008c415c11c5c9bc.png)
and pixelize them like this:
(http://s8.hostingkartinok.com/uploads/images/2016/08/ccb1bd528c43e55a0fca85468feee6bb.png)
To spit magma a greater distance, perhaps try minecart cannon?
I thought about it but it'll probably will appear very ugly in visualizers. I don't yet decide what will be my next fort, right now I think about a magma hologram - several floor hatches that open and close in certain order so the magma flowing out creates a 3D-blob of some sophisticated shape, for example, a dwarf.