Descartes' Heart Curve

A cardioid is the path traced by a fixed point on one circle as it rolls around the circumference of another circle of the same radius, touching it as it goes. Its heart-like shape gives it its name. The curve comes from the thirteenth letter Descartes wrote to Princess Christina of Sweden: r=a(1-cosθ). The equation he wrote on the title page of his mathematics book was the most obscure and timid confession of love. This is the story of one top student being forcibly turned gay by another: a reserved, awkward receiver × a shameless, lecherous aggressor.