" <------------------------- sam064.txt ---------------------------->
  p # 2 3 5 7
  L # e # 3 4 R I 12
  L # x # 3 4 R 'ABCDEFGHIJKL'
" <--- Grade up ---------------------------------------------------->
  A 3 5 3 2
" <--- Grade down -------------------------------------------------->
  W 3 5 3 2
" <--- Deal -------------------------------------------------------->
  a # 5 ? 15
  &/aEI15 " should always produce 1
" <--- Matrix inverse ---------------------------------------------->
  M 2 2 R 1 1 0 1
" <--- Matrix division --------------------------------------------->
  (2 2 R p) M 2 2 R 1 1 0 1
)off