For positive integers t; v; k and l satisfying k > t and v > k; a t-design D with parameters ðv; k; lÞ is a set X of v points, together with a collectionB of subsets, called blocks, such that each block contains exactly k points and each t-tuple of points is contained in exactly l blocks. A t ðv; k; lÞ design is simple if repeated blocks are not allowed and is non-trivial if not all k-sets of p...