A machine that lets you put portal’s traversing any % in height but only 40m base amount, and 40m added with each coil. The base machine would be good for mine shafts or lifts.
Coils could be constructed from compact oort to add an end game to the situation and still use some oort, and then to power the portal it costs spark per min.
Or make some fuel for the machine that uses some oort but mainly spark - perhaps this machine would have a max range and no coils.
If like normal machines, perhaps each could power up to 4 portals with spark costs, only 1x2 portals allowed. Portals could be fuelled by spark line to top or bottom of portal.