Sheet item with non-circular holes

A sheet system comprising a sheet having an edge and at least one generally triangular, closed-sided hole positioned adjacent to but spaced apart from the edge, wherein said hole is shaped as an equilateral triangle having a base and two legs of a length equal to that of said base, wherein said base of said triangle is oriented generally parallel with said edge of said sheet, wherein said legs are interconnected by a rounded vertex corner positioned closer to said edge of said sheet than and opposite of said base of said triangle, and wherein said base and respective ones of said legs are interconnected by rounded base corners with said rounded vertex corner being positioned closer to said edge of said sheet than said rounded base corners wherein each of said vertex corner and said base corners of said triangle has an average radius that is at least about 5% of a length of the base of the triangle, and less than 45% of a length of the base of the triangle, further comprising a reinforcing material coupled to at least a portion of the sheet, the reinforcing material disposed around the entire perimeter of the closed-sided hole, wherein said vertex corner of said triangle has a greater average radius of curvature than the average radius of curvature of each of said base corners of said triangle.