“Purty” is a regional variation of the word “pretty.” It sounds a bit more folksy, and it works well with this short, funny poem.
On a purty summer day
Driving a purty sports car
Down a purty wide avenue
Listening to purty radio tunes
Hey, it’s a purty life
This purty flashy, speedy car
With its purty big engine
How does purty fast feel?
Yes, cruisin’ purty fast now
With purty bright lights flashing
Seeing a purty police car
Hmm, this speeding ticket ain’t purty