A small static shape in the game of life, found commonly in the
wild. The block is both volatile and regenerative, making it a
particularly interesting shape as far as its involvement with
other cells. Any cell within 2 units of it, other than directly
along a diagonal, can produce a reaction from the block, and any
cell adjacent to the block (such as the result of such reaction)
kills adjacent cells within the block, but a lone block with one
corner missing regenerates that corner in the next generation.
See beacon. Useful for growing herbs in ADOM.  1) (shortened
from mental block) A sort of organic stoprule or safety valve
that prevents people from going crazy when they consider thought
experiments exploiting combinatorial explosion. "It's a good
thing I had a block just then! I was getting a trifle dizzy when
he started going on about storing all the possible descriptions
of the universe in a book made out of tiny galaxies pretending
they're electrons."  2) A small but obdurate obstacle preventing
the smo