The poem
You cannot see the walls that divide your hand From his or hers or mine when you think you touch it.
You cannot see the walls because they are glass, And glass is nothing until you try to pass it.
Beat on it if you like, but not too hard, For glass will break you even while you break it.
Shout, and the sound will be broken and driven backwards, For glass, though clear as water, is deaf as granite.
This fraudulent inhibition is cunning: wise men Content themselves with breathing patterns on it.