For a set of n contact points on the boundary of a 2D object together with their contact normals, we present an output sensitive heuristic algorithm for computing a large number of combinations of four points from this set that achieve force closure under the frictionless contact assumption. The proposed algorithm runs in 0(n2 lg n + K) where K is the number of different solutions. Our algorithm is capable of computing significant portion of the solutions in various test cases. Preliminary implementation is described along with experimental results showing efficiency of the algorithm