Nothing says it better than Margaret Atwood (one of my favorite poets by the way).
You begin this way:
this is your hand,
this is your eye,
this is a fish, blue and flat
on the paper, almost
the shape of an eye
This is your mouth, this is an O
or a moon, whichever
you like. This is yellow.
Outside the window
is the rain, green
because it is summer, and beyond that
the trees and then the world,
which is round and has only
the colors of these nine crayons.
This is the world, which is fuller
and more difficult to learn than I have said.
You are right to smudge it that way
with the red and then
the orange: the world burns.
Once you have learned these words
you will learn that there are more
words than you can ever learn.
The word hand floats above your hand
like a small cloud over a lake.
The word hand anchors
your hand to this table
your hand is a warm stone
I hold between two words.
This is your hand, these are my hands, this is the world,
which is round but not flat and has more colors
than we can see.
It begins, it has an end,
this is what you will
come back to, this is your hand.