Let me give you an example, just like when we were young, we usually played a childish game. A little ant assumes that he is crawling along a straight line, and we have a moth ball pointing to this straight line, so the little ant makes a circle and then enters the second dimension. Of course, you look down on him and say, "What's this called?" Then you draw a circle and circle the ants inside, hehe! You're proud of it. Look down on this ant and see how it comes out! He tasted three flavors once, and the ants went out. The ant thought about it, jumped out, and once entered the four dimensions. Think again, hehe! This is quite big! Imagine if you put him in a ball, he can't get out no matter what he drinks! ! If you enter 4-D again, then you can go out easily! !

W=ax+by+cz+dt, where x.y.z.t is a four-dimensional unit vector. If you master this formula and enter four dimensions, there is no problem! !