Two Worlds 

It is said that when the mathematical god formed a world in which people could live some people asked him.
Why we would have to live in 3D world?

The mathematical god answered.
The 3D world is born from the 4D world. This conception is a very simply way how to transform immortality in a life.

After a while the mathematical god added.
The real life needs infinity. And this is a part of 3D world but not of 4D world. Infinity is needed for defining such sequences as are for example human generations.

PS: The story "Why we live in the 3D world" is here to help readers/players understand the basic principle which enabled the creation of the games.