ABCD| ABC |ABC | AB D| |AB D AB |AB |AB A CD| | |A CD A C |A C | |A C A D| |A D| A |A |A |A BCD| | | | BCD BC | BC | | | BC B D| | B D| | B D B | B | B | | B CD| | | CD| CD C | C | | C | C D| | D| D| D ()