A Circle

Last week I took my three year old for a physical exam. The pediatrician did all the routine exams for about 15 minutes, and reported that every thing looked fine.
At the end, we had little chat.
Doc: "Does she talk much? She probably is shy now."
Mother: "Yes, she talks a lot, in 3 languages."
Doc: "Wow, that's wonderful! Does she draw circles? Oh, this is the last question." (apologetically)
Mother: "Yes, she has been drawing circles since many months ago.
At the end, the 3-year-old got two big Cinderella stickers, and happily went home.
But, the mother was puzzled.
Is the ability of drawing a circle such a significant milestone
at this stage?
Does it just show that the child has fine motor skills or lack of them?
A circle must be more than just a circle.
This reminded me of a book I read about 2 years ago, Young at Art by Susan Striker. I have learned the importance of scribbling, and the meaning of that, and that has lead me to start collecting her "work/play projects".
The projects in the book are wonderful, and are really designed to allow children to express themselves. While doing those projects with her, I am more aware of my child action and the work process from a child's perspective.
It made me think about the purpose of art, and how it has affected me when I was a kid.
There were explanations on what is creative activities and what is not, such as coloring book and puzzles.
It also explained the natural progressions from linear scribbling to circular motion, from simple circles to with many combination of strokes and dots, from swirl circles to the universal mandala forms.
It is very important to let or encourage the child to tell adult what they think the creations are, instead of the other way around. I thought that was a very good advice, because I really like to see how far and wild the child imagination would go.
In general, it is a helpful and resourceful book with information on suggested books, songs related to art projects, locations for art supplies and materials.
Another similar book is First Art by MaryAnn Kohl. It seems like another fun book to explore with my child. Or if any of you have read it, tell us what you think.
UPDATE:
If I want to look for quick tips on project, the First Art by MaryAnn Kohl is great. But, personally I like the Young at Art by Susan Striker better, because the concepts of child art are explained in the book. Also, the range of age is covered more, till kindergarten in the Young at Art, while the First Art is for toddler up to two years old.
One quote from the Frist Art to remind myself,
"... each stage of children's drawing development is very precious, and will never come again." ---Mia Johnson, Understanding and Encouraging Your Child's Art