The human brain is made up of two halves, a left and a right brain.
There's a big fold in the human brain that divides our brain into two different and unique parts. Well, almost different.
These parts are connected to each other by a thick network of nerves at the base of each brain. This only link between the two parts is called the corpus collosum.
It's just like an Ethernet cable or network connection between two amazingly fast and very powerful computer processors, each running a different program from the same input. The left side of our body is connected to the right side of our brain and the right side of our body to the left side of the brain.
For whatever reason, nature did this intersection; it even applies to our eyes, which process the majority of our sensory data on opposite sides of the brain