Abstract: A container formed from a blank to define indexing longer walls having an inward incline but a double thickness provided by a foldline at the tops thereof so that the indexing projections are receivable within corresponding openings in the base of a corresponding container. Each part of the indexing walls has an extension such that at each end thereof one extension attaches to the outside of an end wall while the other attaches to the inside of an end wall with preferably that attaching to the inside of an end wall through a pair of parallel vertical folds providing a support at least in part for the weight of a stacked container.