And there, the Window

It looks like a door. It's an open hand.
It looks like a gate. It's a heart on hinges;
me at the threshold, U on the inside,
fullness and emptiness, sound and no sound.
Art and no art thou art.

U are the grand stand. I am a split
divided by a million, again divided by a billion
and then a trillion into operations infinite,
up the spiral staircase where "out" is a tower
and there the window.