A rose curve is r = sin(kθ). Here k = b/a, with a = 1, 3, 7 down the rows and b = 2, 4, 8 across. With k = p/q in lowest terms and pq even, the rose has 2p petals and closes after θ = 2qπ. Each a is odd and each b a power of 2, so p = b and q = a: each column has 2b petals, 4, 8