Abstract: A package having an openable end, and a closure structure for closing the openable end. The closure structure comprises at least one aperture-set which includes a respective aperture in each of at least two sheet segments of the package. Each aperture has a tab which presents a free end depending within its respective aperture from a flex line. The flex line partially bounds the respective aperture, and respective apertures in each aperture-set are generally adjacently registrable in a covered position. The at least two sheet segments are held in the covered position by displacing the distal end of the tab associated with each respective aperture of an aperture-set through at least the next adjacent respective aperture of the aperture-set.