How To Explain The Holy Trinity

My favorite way to explain The Holy Trinity to folks is as follows...

The Trinity is like a game of 'Dungeons and Dragons.'

In the place of The Father you have the Game Master... an actual person who exists outside the game world.

For the Son, you have the Game Master's avatar...his player character...who he is in the game world.

The Holy Spirit, is the rules of the game as applied by the Game Master... because the 'rules' are the Game Masters 'Will.'

All three of those represent the same person.

Simple.