damm←{⎕IO←0
    tbl←⍉⍪0 3 1 7 5 9 8 6 4 2
    tbl⍪← 7 0 9 2 1 5 4 8 6 3
    tbl⍪← 4 2 0 6 8 7 1 3 5 9
    tbl⍪← 1 7 5 0 9 8 3 7 2 6
    tbl⍪← 6 1 2 3 0 4 5 9 7 8
    tbl⍪← 3 6 7 4 2 0 9 5 8 1
    tbl⍪← 5 8 6 9 7 2 0 1 3 4
    tbl⍪← 8 9 4 5 3 6 2 0 1 7
    tbl⍪← 9 4 3 8 6 1 7 2 0 5
    tbl⍪← 2 5 8 1 4 3 6 7 9 0
    0={tbl[⍵;⍺]}/⌽0,⍵
 }