The Stair 

The limbs of the giant spruce that leans
  So close to the house, have formed
A kind of stair, a walkway
  Up to the summit. The squirrel that lives here
Scorns to descend it step by step‚
  But with an insane bravado runs
To a branch end, then drops
  Accurately off and, six flights down,
Arrives upright, pinecone in hand‚
  To remain there, tear at and eat it:
Perfectly secure, he is perfectly sane.
  Today, comes snow. We should accept
The long-standing invitation
  To climb those now carpeted treads‚
But snow and common sense say no—
  Such analogues are not to be acted on.
And yet we inhabit our images: squirrel
  Can even seem a god of heights‚
The tree his spruce fane. The animal
  Is asleep, and if he were not, he would be
Unconscious of the place devised which we
  Take into our minds and so ascend
The real by way of the imaginary tree:
  Both lean to the house together‚
And, even without their deity, can teach
  These wooden walls that this house is a tree house:
We live in a place always just out of reach.