sub mmult(@a,@b) {
    my @p;
    for ^@a X ^@b[0] -> ($r, $c) {
        @p[$r][$c] += @a[$r][$_] * @b[$_][$c] for ^@b;
    }
    @p;
}

my @a = [1,  1,  1,   1],
        [2,  4,  8,  16],
        [3,  9, 27,  81],
        [4, 16, 64, 256];

my @b = [  4  , -3  ,  4/3,  -1/4 ],
        [-13/3, 19/4, -7/3,  11/24],
        [  3/2, -2  ,  7/6,  -1/4 ],
        [ -1/6,  1/4, -1/6,   1/24];

.say for mmult(@a,@b);