So, toroid fusion plant (almost) finished.
All it needs is recolouring of some parts (becuase I have found that there are unwanted night lighting pixels) and preparation of dat file.
In attachment is PNG file and GIMP file with layers as I exported them from original software I use.
I'd consider seperating the graphics to have a reusable 2x2 for the torus and the 1x2 building with four rotations, so you only need 12 images instead of 24.
You can use tilecutter both for the splitting and special colors: https://forum.simutrans.com/index.php/topic,20149.0.html
It is not 3*2 - but 6*4. I did it really big. But it is only detail. So, needed images count (after tile cutting) is much greater.
And I am not sure if I understand your suggestion correctly, so ... Headquarters with fields? For greater power production? Very interesting way how to supply great many factories.
I know that for GIMP was add-on capable to do the same - and more precisely. I think I downloaded it (like many other ut). But I did not find it in collection of various tools I have downloaded.
Ready for installing into game, using and (at mainly) further testing. Toroid fusion power plant.
Current dat file is the second version.
Electricity production is really great (1000) - because fusion power plants should have really great output. And with people and post it may increase in allowed range (that doubles production). It is very high but still, probably unable to support all factories alone (and mostly if there are many industry chains).
However, may it be that there are some lines that are not really needed. So, later changes may be needed.