-- learn our difference operators:
    pos-diff-R0-R |*> #=> subtraction-invert[255] 5 pos (R0 |_self> + - R |_self>)
    pos-diff-G0-G |*> #=> subtraction-invert[255] 5 pos (G0 |_self> + - G |_self>)
    pos-diff-B0-B |*> #=> subtraction-invert[255] 5 pos (B0 |_self> + - B |_self>)  

    -- copy values to old-values:
    |null> => map[R,R-copy] rel-kets[R] |>
    |null> => map[G,G-copy] rel-kets[G] |>
    |null> => map[B,B-copy] rel-kets[B] |>

    -- apply our operators:
    |null> => map[pos-diff-R0-R,R-tmp] rel-kets[R0] |>
    |null> => map[pos-diff-G0-G,G-tmp] rel-kets[G0] |>
    |null> => map[pos-diff-B0-B,B-tmp] rel-kets[B0] |>

    -- copy values to R,G,b:
    |null> => map[R-tmp,R] rel-kets[R-tmp] |>
    |null> => map[G-tmp,G] rel-kets[G-tmp] |>
    |null> => map[B-tmp,B] rel-kets[B-tmp] |>