The embodiments of the present invention provide a blank foldable material that may be configured to form a container. When formed, the container is self-locking and includes a rollover panel assemblies formed by spaced apart fold lines that forms bearing surfaces for vertically stacked containers. The container includes a inside taper that functions to prevent telescoping of vertically stacked container, and to hold the various corner panels in their proper location. The blank is configured to form a container that includes corners having multiple thicknesses for strength and stability. The container is self locking, easy us manufacture yet high strength.