context function 2: grid-simm

        grid-simm(|op: image1>, |op: image2>)
        grid-simm(|op: image1>, |op: image2>) ket
        returns the grid similarity of all the sequences defined with respect to the image1 operator
        and those defined with respect to the image2 operator
        The intended use case is to map images to grids of sequences, and then compare them
        The result is returned as the coefficient of |grid simm>,
        Or, if ket is specified, then the result is the coefficient of that ket
        Where the result should be in range [0,1]

        -- if only 1 pattern is defined for each operator,
        -- it should return the standard result for simm(seq1, seq2)
        -- Eg:
        image1 |0> => |a> . |b> . |c>
        image2 |0> => |a> . |> . |c>

        -- First, standard simm:
        simm(image1|0>, image2|0>)

        -- Now grid-simm:
        grid-simm(|op: image1>, |op: image2>)

    see also:
        simm, similar-grid