| 摘要 |
A sheet of paper or like material having a first and a second set of concertina folds with the second set of folds being transverse to the first set when the sheet is folded. The sheet is provided with two stiff portions at diagonally opposite corner segments of the sheet, so that the sheet can be unfolded with a single movement and possibly using only one hand to grasp and unfold the sheet. |
