Kindergarten: The essence of 2

I'll show you how powerful 2 is. Without it we would not have night and day. 

We need two to make opposites. Wet and dry, smooth and bumpy, short and tall, wrong and right, light and dark. Are there more opposites?

And if we didn't have opposites, we couldn't appreciate things as fully as we do. If we never knew what sadness felt like, we would not know how good it is to be happy. We would exist, but without context, or depth. 

On every spectrum there are two sides.

Play the Beatles song, Hello Goodbye. 

https://youtu.be/ywZqBGHDTlA