On page 241 Focus on Poetry Animals Dinner Together: sitting by the barbecue waiting for sausages and hot dogs blue-gray smoke the same color of the sky I see a tiny spider walking down the sky with tiny six footed steps down down in a perfectly straight line all the way down to the floor then back up the same line rising from one cloud up to another, a silver speck glistening at its mouth, climbing the invisible ladder. The question is what is all about?

2 answers

I think the narrator sees a speck of ash in the smoke from the barbecue and imagines it to be a tiny spider. The bit of ash from the fire looks like it could be a spider walking among the clouds, in the sky.

Do remember, too, that we don't have the same book you do, so the page number, etc., mean nothing to us tutors.
And Houghton Mifflin is not the author. It's the company that published your textbook.