Robert Sacks' 1994 polar variant of the Ulam spiral: each integer n sits at radius √n, angle 2π√n. The square root rate gives perfect squares a single ray, and primes settle into curved trails along quadratic polynomials.
n² + n + 41 (Euler's polynomial, prime for n = 0…39) traces an arc you can find by eye. The radial spokes are perfect squares. Twin primes (highlighted in the gold toggle) cluster in pairs you can see clinging together. Switch the color mode to residue mod 30 to make the eight residue classes of primes > 5 visible — that's the wheel factorization made geometric.