Ramsey's theorem guarantees that in any 2-coloring of edges of K_n, a monochromatic clique of size r or s must appear when n ≥ R(r,s). The Ramsey number R(3,3)=6, R(4,4)=18, but R(5,5) remains unknown (between 43 and 48). Watch random 2-colorings hunt for monochromatic triangles and cliques.