''Tetra'' is a sculptural seating ensemble consisting of six groups of polished stainless steel truncated tetrahedrons, each containing one ''table'' and three ''seats.'' These groupings are placed so that together they create one large triangle. This triangle in turn is placed on a circular bed of gravel, graded so as ot create a horizontal space on the otherwise gently sloping lawn. After the sphere, the tetrahedron is the simplest geometric form. The staggered high/low rhythms of the tetrahedral tables and seats will create many arrays of patterns and textures as the viewer moves past. Polished stainless steel is a sensitive reflector of light. Over the course of an hour, a day or the year, varying light will itself transform the ensemble into an ever-changing display.