A granular material handling device formed from a sheet of material having a top surface and a bottom surface, the device comprising: a rectangular middle panel comprising a central rectangular subpanel hingably joined to a lower rectangular subpanel along a first fold line and hingably joined to an upper rectangular subpanel; a left panel hingably joined to a left edge (114, 119, 120) of the rectangular middle panel and comprising a plurality of left panel facets (F4, F5, F6, F7, F8) hingably joined to each other including a leftward right triangular facet hingably joined to a left edge of the central rectangular panel perpendicular to the first fold line, and hingably joined to a leftward adjacent facet at a second fold line collinear with the first fold line; and a right panel hingably joined to a right edge (114', 119', 120') of the rectangular middle panel and comprising a plurality of right panel facets (F4', F5', F6', F7', F8') hingably joined to each other including a rightward right triangular facet (F6') hingably joined to a right edge of the central rectangular panel perpendicular to the first fold line, and hingably joined to a rightward adjacent facet (F7') at a third fold line collinear with the first fold line; wherein the lower rectangular subpanel and upper rectangular subpanel are pivotable with respect to the central rectangular subpanel to an opposed position forming an enclosed cavity; wherein the left panel facets (F4, F5, F6, F7, F8) are pivotable with respect to each other so as to position the leftward right triangular facet perpendicular to the central rectangular panel and define a left end of the enclosed cavity, and to position a remainder of the plurality of left panel facets (F4, F5, F7, F8) within the enclosed cavity; wherein right panel facets (F4', F5', F6', F7', F8') are pivotable with respect to each other so as to position the rightward right triangular facet (F6') perpendicular to the central rectangular panel and define a right end of the enclosed cavity, and to position a remainder of the plurality of right panel facets (F4', F5', F7', F8') within the enclosed cavity, thereby placing the device in a closed configuration; wherein the first fold line, second fold line, and third fold line define a collinear fold line; and wherein, simultaneously, the leftward right triangular facet is foldable 180 degrees with respect to the leftward adjacent facet along the collinear fold line, the central rectangular subpanel is foldable 180 degrees with respect to the lower rectangular subpanel along the collinear fold line, and the rightward right triangular facet (F6') is foldable 180 degrees with respect to the rightward adjacent facet (F7') along the collinear fold line to render the device in a flat configuration. a rectangular middle panel comprising a central rectangular subpanel hingably joined to a lower rectangular subpanel along a first fold line and hingably joined to an upper rectangular subpanel; a left panel hingably joined to a left edge (114, 119, 120) of the rectangular middle panel and comprising a plurality of left panel facets (F4, F5, F6, F7, F8) hingably joined to each other including a leftward right triangular facet hingably joined to a left edge of the central rectangular panel perpendicular to the first fold line, and hingably joined to a leftward adjacent facet at a second fold line collinear with the first fold line; and a right panel hingably joined to a right edge (114', 119', 120') of the rectangular middle panel and comprising a plurality of right panel facets (F4', F5', F6', F7', F8') hingably joined to each other including a rightward right triangular facet (F6') hingably joined to a right edge of the central rectangular panel perpendicular to the first fold line, and hingably joined to a rightward adjacent facet (F7') at a third fold line collinear with the first fold line; wherein the lower rectangular subpanel and upper rectangular subpanel are pivotable with respect to the central rectangular subpanel to an opposed position forming an enclosed cavity; wherein the left panel facets (F4, F5, F6, F7, F8) are pivotable with respect to each other so as to position the leftward right triangular facet perpendicular to the central rectangular panel and define a left end of the enclosed cavity, and to position a remainder of the plurality of left panel facets (F4, F5, F7, F8) within the enclosed cavity; wherein right panel facets (F4', F5', F6', F7', F8') are pivotable with respect to each other so as to position the rightward right triangular facet (F6') perpendicular to the central rectangular panel and define a right end of the enclosed cavity, and to position a remainder of the plurality of right panel facets (F4', F5', F7', F8') within the enclosed cavity, thereby placing the device in a closed configuration; wherein the first fold line, second fold line, and third fold line define a collinear fold line; and wherein, simultaneously, the leftward right triangular facet is foldable 180 degrees with respect to the leftward adjacent facet along the collinear fold line, the central rectangular subpanel is foldable 180 degrees with respect to the lower rectangular subpanel along the collinear fold line, and the rightward right triangular facet (F6') is foldable 180 degrees with respect to the rightward adjacent facet (F7') along the collinear fold line to render the device in a flat configuration.