Antimatter by Russell Edson (1973)

On the other side of a mirror there’s an inverse world, where the insane go sane; where bones climb out of the earth and recede to the first slime of love.

      And in the evening the sun is just rising.

      Lovers cry because they are a day younger, and soon childhood robs them of their pleasure.

      In such a world there is much sadness which, of course, is joy . . . 

With thanks to The Poetry Foundation.