geometry
MULTIPOLYGON Z (((30 10 40, 40 40 80, 20 40 60, 10 20 30, 30 10 40)))
MULTIPOLYGON Z (((30 20 50, 45 40 85, 10 40 50, 30 20 50)), ((15 5 20, 40 10 50, 10 20 30, 5 10 15, 15 5 20)))
MULTIPOLYGON Z (((40 40 80, 20 45 65, 45 30 75, 40 40 80)), ((20 35 55, 10 30 40, 10 10 20, 30 5 35, 45 20 65, 20 35 55), (30 20 50, 20 15 35, 20 25 45, 30 20 50)))

MULTIPOLYGON Z EMPTY