"Ear to the Ground"Mulberry Street Theater's commissioning seriesrecently featured world premieres by David Liu and Kun-Yang Lin. Liuwhose exquisite presence and works light up the skate-dance troupe, Ice Theater of New Yorkpresented Visual Reference, in which small Polaroid photos sparked episodes of stretchy, playful, competitive, or dramatic moves. Ryoko Kudo, Jennifer Pike, and Rachael Venner danced pleasantly, and Patrick Alexander's curtain of snapshots clipped to wires created a handsome, if mysterious, backdrop. Since the images were too small and distant, it was impossible to tell what triggered Liu's ideas and to guess why. In the abstract, Zen-inspired Emptiness of Snow, Lin's five disciplined dancers created an icy landscape that was actually anything but empty and static. Complex variety of speed, shape, and group configurationdancers whipped and spun about by imagined wind and thrust to the floor, somehow always very neatlygave this work a poetic sensibility.