Punch line

You keep smiling at behind doors
And bear  witness to the rising wall,
Leaving nothing to room’s chance.

At night you bang the wall in dark
On a serious difference of opinion
About existence of the other room.

You and dog live in a joint wonder.
You smile at her silly joke coming,
She smiling on yours, both mutual.

You smile at visitors softly closing
A door behind them in your room.
You are waiting for the punch line.