1 2 3 4 E E E E * X u t * t u * X * handedness 1 2 3 L handedness 1 2 4 R handedness 1 3 4 R handedness 2 3 4 R sheetS 1 4 sheetS 2 3 sheetD 1 2 length 1 E 5 100 length 2 E 5 100 length 3 E 5 100 length 4 E 5 100