  We study segmented strings in flat space and in $AdS_3$. In flat space, these
well known classical motions describe strings which at any instant of time are
piecewise linear. In $AdS_3$, the worldsheet is composed of faces each of which
is a region bounded by null geodesics in an $AdS_2$ subspace of $AdS_3$. The
time evolution can be described by specifying the null geodesic motion of kinks
in the string at which two segments are joined. The outcome of collisions of
kinks on the worldsheet can be worked out essentially using considerations of
causality. We study several examples of closed segmented strings in $AdS_3$ and
find an unexpected quasi-periodic behavior. We also work out a WKB analysis of
quantum states of yo-yo strings in $AdS_3$ and find a logarithmic term
reminiscent of the logarithmic twist of string states on the leading Regge
trajectory.
