Same recipe, but yields 2 and gives back 3 books when you craft it, since it is
made using a bookshelf. Works with the circular saw to produce various shapes.
a lava source next to any water produces obsidian.
lava flowing into a water source makes basalt.
lava flowing into flowing water makes pumice
This will only work after minetest_game's default/init.lua gets fixed to call
the proper functions. Without that fix, nothing will happen - minetest_game's
default lava cooling code will run instead.
