Folder/portfolio and origami construction for forming it from a rectangular blank

A method for fabricating a portfolio exclusively from a single rectangular blank of sheet material, for storing flat sheet articles, which comprises:

• a) choosing a perfectly rectangular one-piece sheet material blank;
• b) folding said one-piece sheet material blank so as to form two side walls, two end walls, two handle flaps and a bottom surface, said side and end walls being hingedly connected at lower edges thereof to respective edges of said bottom surface, and each of said handle flaps being hingedly connected to an upper edge of a corresponding one of said side walls;
• d) folding all corner portions of said one-piece sheet material blank in an interlocking relationship with adjacent portions of said blank so as to maintain a mechanical alignment between said bottom surface, said handle flaps, said side walls and said end walls;
• and
• e) forming hinge lines on at least two of said side walls and said end walls such that all of such walls may be simultaneously moved between erect and collapsed positions thereof while said corner portions are in said interlocking relationship.

A portfolio for containing flat articles therein, comprising:

• a flat bottom surface having a plurality of edges;
• a plurality of wall members hingedly connected, respectively, to said edges of said bottom surface, said wall members being selectively pivotable between erect and collapsed positions thereof;
• a pair of handle flaps hingedly attached to upper edges of two of said wall members, respectively;
• means for interlocking said wall members and said handle flaps together in a predetermined cooperative alignment;
• means for permitting said wall members to be simultaneously moved between said erect and collapsed positions thereof while said wall members and said handle flaps are interlocked together by said interlocking means;
• said bottom surface, said wall members, said handle flaps, said interlocking means and said means for permitting simultaneous movement all being formed exclusively from a single blank of sheet material having a perfectly rectangular shape;
• and
• said interlocking means including corner portions of said rectangular blank of sheet material which have been folded such that sections of the corner portions are frictionally engaged with each other and operatively engaged with folded sections of said handle flaps.