Building a castle? Building underground sewer systems? Building a space ship? You just might need some arcs to complete the build. These arcs are available in straight, inside and outside corners, and with a little help from the screwdriver they can be rotated into any direction you need.
To register your own nodes as arcs just add this code into your mod:
if minetest.get_modpath("pkarcs") then pkarcs.register_node("your_mod:your_nodename") end