-is available that is passable and not inhabited by a thing of the same same type
-or, if the proliferating thing is animate, any other animate thing.
-
-TT_STOMACH [0-32767]
-Set degree to which things of the selected type suffer from hunger or
-over-satiation: If 0, not at all. Else, each turn a thing of the given type may
-suffer a lifepoint decrement to the chance of the rounded down quotient of the
-satiation score's absolute value by the given value, then again divided by the
-latter. This means that the chance is always zero when the absolute value of the
-satiation score is lower than the given value.