proc transpose &m[][] .
   len n[][] len m[1][]
   for i to len n[][]
      for j to len m[][]
         n[i][] &= m[j][i]
      .
   .
   swap n[][] m[][]
.
m[][] = [ [ 1 2 3 4 ] [ 5 6 7 8 ] [ 9 10 11 12 ] ]
print m[][]
print ""
transpose m[][]
print m[][]