What or who are they?

This task is about making inferences to predict what a poem could be about.
Read the following poem by David Hill (from School Journal, Part 4, no. 1, 2002 or available at NZPoetryBox) in three parts, one part at a time.
 
After reading each part, use the left hand boxes to predict all the things you think the poem is describing. Use the right hand boxes to explain how the evidence in the text, and what you know, supports your predictions.

Question 1Change answer

There they were this morning,
High up on an office block.
Part 1
I think this poem could be describing any one of these things:  because:

Question 1Change answer

There they were this morning,
High up on an office block.
 
One was polishing the sun,
Another rinsing fleecy clouds,
A third rubbing the blue sky.
Part 2
Now I think this poem could be describing any one of these things:  because:
 

Question 1Change answer

There they were this morning,
High up on an office block.

One was polishing the sun,
Another rinsing fleecy clouds,
A third rubbing the blue sky.
 

If I come back tonight,
Will they still be there -
One scrubbing the shooting stars,
Another washing the moon,
A third wiping down the Milky Way?
Part 3
Now I think this poem could be describing any one of these things:  because:
 

Question 1Change answer

Pause, look, and think back: 
How did the verbs 'polishing, rinsing, rubbing, scrubbing, washing, wiping' help you understand what this poem could be about?

Question 1Change answer

The focus of this task has been making inferences. Describe when and how you used any of the following reading strategies:
 
Making connections between what I know  yesno
Asking questions yesno
Creating a picture in my head, or visualising yesno
Identifying the writer's purpose yesno
Identifying the main idea yesno
Summarising yesno
Analysing and synthesising ideas and information yesno
Evaluating ideas and information yesno