  This Letter outlines 20 geometric mechanisms by which limit cycles are
created locally in two-dimensional piecewise-smooth systems of ODEs. These
include boundary equilibrium bifurcations of hybrid systems, Filippov systems,
and continuous systems, and limit cycles created from folds and by the addition
of hysteresis or time-delay. Scaling laws for the amplitude and period of the
limit cycles are compared to (classical) Hopf bifurcations.
