1. A configurable logic element (CLE) for a programmable logic device (PLD), the CLE comprising: a logic block providing two N-input lookup tables (LUTS), the logic block having a first LUT mode wherein the two LUTs have at least one unshared input and a second LUT mode wherein the two LUTs have N shared inputs; and an AB expander configurably interconnecting the outputs of the two LUTs, the AB expander having two or more configurable functions one of which is a multiplexer function from which the AB expander provides the output of an (N&plus;1)-input LUT.