  We give a quantum algorithm for finding a marked element on the grid when
there are multiple marked elements. Our algorithm uses quadratically fewer
steps than a random walk on the grid, ignoring logarithmic factors. This is the
first known quantum walk that finds a marked element in a number of steps less
than the square-root of the extended hitting time. We also give a new tighter
upper bound on the extended hitting time of a marked subset, expressed in terms
of the hitting times of its members.
