We tested the gravitational 1/r^{2} law using a stationary torsion-balance detector and a rotating attractor containing test bodies with both 18-fold and 120-fold azimuthal symmetries that simultaneously tests the 1/r^{2} law at two different length scales. We took data at detector-attractor separations between 52 μm and 3.0 mm. Newtonian gravity gave an excellent fit to our data, limiting with 95% confidence any gravitational-strength Yukawa interactions to ranges <38.6 μm.