Calder's <a target=_blank 
href="http://www.nga.gov/fcgi-bin/timage_f?object=92728&image=21145&c="><i>Little 
Spider</i></a> is well balanced: the fins rotate easily (and shift 
colors due to changing angles as they do).  The legs also look 
balanced well.  <i>J</i> likes this piece.