I saw a youtube video '4th dimension explained by a high school student' . I was very dissapointed in his concept of dimensions. First of all, we do see objects in three dimensions, the view that 3D vision is sort of an X ray vision is false. If an object is not 3D , it would not exist, firstly, where the word exist denotes  'matter in this universe' . When you see a face, you see all three variants of its build, that are the two lengths and the width. I hope the concept of dimensions is clear now.