Can you pat your head and rub your stomach at the same time?  This is sometimes a popular teen challenge. 

Don’t sneer.  At least it’s harmless.

The motions blend.  Your two arms are controlled by different parts of your brain, but those parts are connected to work together.  Or, if you ask them to do different things, they can interfere with each other.

Now add a little brain design.  The controls for your wrists are pretty much independent of the controls for your arms.  So start patting yourself on the head with a wrist motion.  (You can rest the heel of your hand on your scalp if you need to keep your arm from getting involved.)  You will find that the other arm can easily rub your stomach with an arm motion.

Caution!  Do not try this in public. 
On the other hand, if you can get somebody else to try it in public…  
Enjoy that image. 

What you just demonstrated is that modules in your brain can interfere with each other when they try to do different jobs at the same time.  And that you can get the modules to work together if you design the jobs to fit the design of your brain.

All you can do with this trick is look silly.

Right.  Unless you wonder why people think they have conflicts with themselves.  Or unless you have some other jobs that you can adjust to fit the design of your brain.

Self-discipline is an illusion produced by engineering the job.

 Unity

Imagine

The Startalittles
A more useful example.

Other ways to call up brain modules.
Players for your Head Team

Head Teams