The fig. (X) is similar to the
Form VI. So, when a cube is formed by folding the sheet shown in fig. (X), then
is one of the faces of the cube. However, the cube in fig. (1) has two such faces and fig. (4) has a face which is completely shaded. So, these two cubes cannot be formed. Hence, only the cubes in figures (2) and (3) can be formed.