  General laws of black-hole dynamics, some of which are analogous to the laws
of thermodynamics, have recently been found for a general definition of black
hole in terms of a future outer trapping horizon, a hypersurface foliated by
marginal surfaces of a certain type. This theory is translated here into
spin-coefficient language. Second law: the area form of a future outer trapping
horizon is generically increasing, otherwise constant. First law: the rate of
change of the area form is given by an energy flux and the trapping gravity.
Zeroth law: the total trapping gravity of a compact outer marginal surface has
an upper bound, attained if and only if the trapping gravity is constant.
Topology law: a compact future outer marginal surface has spherical topology.
Signature law: an outer trapping horizon is generically spatial, otherwise
null. Trapping law: spatial surfaces sufficiently close to a compact future
outer marginal surface are trapped if they lie inside the trapping horizon.
Confinement law: if the interior and exterior of a future outer trapping
horizon are disjoint, an observer inside the horizon cannot get outside.
