Danny Hillis has finished work on the second prototype of the Clock of the Long Now. Standing nine feet tall, this functioning clock provides a close approximation of the current plans for the full-size 60 foot version that will eventually reside in a mountain cave in Nevada. Hillis is still exploring many different ideas for how to construct the clock and what types of displays it will contain (how do we map our notion of hours, or centuries?) I plan to make the trek to visit the clock when it is finished, and I expect that the end result will be equally beautiful to this prototype, but very different.