What is Tree-ears greatest satisfaction in chapter four

During this time, Tree-ear is assigned to the drain pits where he mixes the clay with water, runs it through a sieve, and drains it to prepare it both for the wheel and for the glaze. It is tedious work that Tree-ear feels is made more difficult by Min's stubborn insistence that the clay be processed more than four or five times in some instances. Time passes quickly, with Tree-ear rotating from cutting wood, to cutting clay and draining the clay.