O

Alone, a mouth
Open in wonder,
Add one hydrogen for
Caustic, voiced surprise
Or Santa’s laugh;
Add two for water.

Doubled, nostrils inhaling
The breath that burns,
Craved in proxy by
Our deoxy genes.
Too little asphyxiates;
Will too much create
An oxymoron? 

Tripled, a protective layer
Dials an Oz-zone emergency;
Quadrupled, prefix with
Phosphorus to offend noses
And grow gardens.

Alone, a mouth
With nothing to say.
Add one nitrogen for
Signals, active or denied;
In the dentist's chair,
Add two for laughter.

Doubled, add one carbon,
And the mouth,
Now glib in its glass house,
Blows unseen warmth
Upon the world.