It was impossible to fold a piece of letter-sized (8.5" x 11", 216 mm × 279 mm) 20 lb (75 g/m²) copy paper with perpendicular folds more than seven times. The thickness of the paper exponentially grew with each successive fold, and after the seventh fold the paper was just too thick to fold without breaking. Grant showed if you fold the paper in the same direction 4 times than 4 times the other way, it is possible to fold the paper 8 times. The MythBusters then laid out a football field-sized sheet of interconnected paper (170 ft x 220 ft, 51.8 m x 67.1 m), and due to the reduction of its area-to-thickness ratio (and with help from a steam roller and a forklift), were able to perpendicularly fold the paper 11 times. Other methods of folding a piece of paper (such as with alternating folds) proved able to break the fold threshold of 7 for letter-sized paper, and perpendicular folds of more than 7 are theoretically possible with thinner paper.