To give a wonder that the lower part shape of a block main body is deformed to an opponent by providing a deformation means constituted of a slope in the block main body, inverting the block main body to the left and right and showing the block main body from an obliquely upper side part on a front surface side and from the obliquely upper side part on a back surface side to the opponent.

Since the deformation means 2 of a projection part constituted of the slope 17 or the like and the deformation means of a recessed groove are provided in the block main body 1, a structure is simple. Also, by inverting the block main body 1 to the left and right and showing the block main body 1 from the obliquely upper side part on the side of a front surface 12 and from the obliquely upper side part on the side of a back surface 13 to the opponent, the wonder of the deformation of the lower part shape of the block main body 1 is given to the opponent and its operation is simple.