By David A. Keeps Do you like the architectural look of built-in bookshelves but need more flexibility in design? Then embrace the freestanding case. Colorful contemporary designs often come in Lego-like modular units that can be configured in multiple ways and deployed as sculptural room dividers. The Urban modular shelf, designed by Claudio Bellini for Casamania, is an L-shaped plastic unit available in a spectrum of colors. It can stand alone or be stacked to create a variety of shapes. Cost: $750 for one, $699 each if you buy at least two. Functions in Santa Monica, www.functions.cc.