An end closure design for a paperboard container having four or more end panels that form the end closure hingedly joined respectively to four side panels connected to each other by parallel, spaced apart fold lines. Each of the hinged end panels has a straight free edge parallel the hinged edge and each free edge has two spaced apart notches of the same shape and size cut therein, each positioned the same distance from the parallel, spaced apart fold lines such that when the panels are folded over, a notch from each end panel interlocks with a notch from an adjacent end panel. An opposing two of the hinged end panels also include two diagonal score lines, each extending from an interior edge of the notches to the interior corner formed by the fold lines between the end closure panel and its respective side panel. To form the end closure, the end closure panels without the diagonal score lines are folded inwardly, then the end closure panels with the diagonal score lines are folded inwardly. Pressure is applied (by pushing) to the central portion of the two panels with score lines between the score lines to cause adjacent and overlapping notches to interlock to form the end closure. The resulting container has an end with a central open area and four interlocked notches at the open area's corners.