A knockdown container or display in the shape of a 3-dimensional container is provide which comprises of two main element types, namely Sheet elements and Edge elements. In this design, all of the main elements of the container are joined one to another by sliding with respect to each other in a sequence that make an open or closed display or container that can easily assembled or disassembled. In particular, the edges of the Sheet elements have a shape that is fitted into matching slots of the Edge elements. The position and orientation of elements are such that they securely restrict unwanted movement of the elements with respect to one another, while minimizing the number of needed fasteners or number of additional restricting components needed to secure the Edge elements.