It is this operation +./ . *. we rewrite in peculiar ways for unknown reasons? [ x=: 1 0 1 1 0 1 0 1 1 0 [ y=: 5 6 $1 0 0 0 0 0 0 1 0 1 1 0 0 1 0 0 0 1 0 0 0 0 1 1 0 1 1 1 0 1 1 0 0 0 0 0 0 1 0 1 1 0 0 1 0 0 0 1 0 0 0 0 1 1 0 1 1 1 0 1 x +./ . *. y 1 1 0 0 1 1 /Erling