関連ワード:  what is a 4d shape    what is a 4d shape called    what is a 4d shape look like    what is a 4d shape in real life    what is a 4 dimensional shape called    what makes a 4d shape    what is the 4d shape of our universe    what defines a 4d shape    what is the 4d shape of the universe    what is the volume of a 4d shape called