code: function multiply_matrices(l, r) {
            var al = l[0];
            var cl = l[1];
            var el = l[2];
            var bl = l[3];
            var dl = l[4];
            var fl = l[5];
  
            var ar = r[0];
            var cr = r[1];
            var er = r[2];
            var br = r[3];
            var dr = r[4];
            var fr = r[5];
  
            var a = al * ar + cl * br;
            var c = al * cr + cl * dr;
            var e = al * er + cl * fr + el;
            var b = bl * ar + dl * br;
            var d = bl * cr + dl * dr;
            var f = bl * er + dl * fr + fl;
  
            return [a, c, e, b, d, f];
        }
docs: /*
  ╔═        ═╗   ╔═        ═╗   ╔═     ═╗
  ║ al cl el ║   ║ ar cr er ║   ║ a c e ║
  ║ bl dl fl ║ * ║ br dr fr ║ = ║ b d f ║
  ║ 0  0  1  ║   ║ 0  0  1  ║   ║ 0 0 1 ║
  ╚═        ═╝   ╚═        ═╝   ╚═     ═╝