For committed library enthusiasts, a short diversion a block east on Waterman takes in the Sciences Library, where the architects of Rockefeller Library shifted from horizontal to vertical. They seem to have been more attracted to the glory that might accrue to a tower at the true summit of College Hill than concerned with the practicality of a stack of relatively small floors for an ever-expanding collection. The design derives from a series of contemporaneous buildings in which floors were bridged between corner towers containing stairs, elevators, and utility stacks, possibly the first and the most influential being a classroom and laboratory tower by I. M. Pei at Massachusetts Institute of Technology.