I use the following (self-composed) rhyme with Pete the Cat: I Love My White Shoes, by Eric Litwin, to illustrate color-mixing. Graphics were borrowed from the "Pin the Shoe on Pete" printable at Pete the Cat's website:
Pete had a pair of blue shoes.
What a lucky fellow!
He stepped in a pile of bananas.
They were colored yellow.
He squished and swished and stomped around,
Like you have never seen,
And when he looked down at his feet,
His shoes had turned bright green!
Pete had a pair of red shoes.
Red, yes, it was true.
He stepped in a pile of blueberries
They were colored blue.
He squished and swished and stomped around,
And then he took a bow.
When he looked down at his feet,
His shoes were purple now!
Pete had a pair of yellow shoes.
"It's all good," he said.
He stepped in a pile of strawberries.
They were colored red.
He squished and swished and stomped around,
Although I don't know why.
When he looked down at his feet,
His shoes were orange, oh my!
