  A zero-one sequence describes a path through a rooted directed binary tree
$T$; it also encodes a real number in $[0,1]$. We regard the level of the
external node of $T$ along the path as a function on the unit interval, the
silhouette of $T$. We investigate the asymptotic behavior of the resulting
stochastic processes for sequences of trees that are generated by the binary
search tree algorithm.
