We construct a digraph G whose vertices are the single parts, modules, and finished products occurring in an industrial process. We want the edges to signify how many single parts or intermediary modules are needed for assembling bigger modules or finished products. That is, we assign weight w(i, j) to edge ij if we need w(i, j) units of part i for assembling product j. G is called the gozinto graph. In most cases, the modules and products are divided into levels of the same rank, where the finished products have highest rank, and basic parts (which are not assembled from any smaller parts) lowest rank; that is, the products and modules are divided into disposition levels. The notion of ranks used here is the same as in Exercise 3.6.3;