WordNet (r) 3.0 (2006):

blocky
    adj 1: resembling a block in shape [syn: blockish, blocky]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "blocky":
   chubby, chunky, dumpy, fat, podgy, pudgy, pug, pugged, retrousse,
   snub-nosed, squat, squattish, squatty, stocky, stubbed, stubby,
   stumpy, thickset, tubby, turned-up