>>337
1-1
1-2 2-2
1-3 2-3 3-3
1-4 2-4 3-4 4-4
1-5 2-5 3-5 4-5 5-5
1-6 2-6 3-6 4-6 5-6 6-6
すなわち (6+5+4+3+2+1)×4面