Jeenyus School Invention #2: Chalk Skid Tires

Skidding is one of the best professions there is for kids.  Think about it, it only requires a bike with tires and you can do it all day long.  With these new Chalk Skid Tires, kids can also create chalk masterpieces.
            Because the outside of this tire is made of chalk, the child need only hit the breaks to produce a very long beautiful chalk line on any surface.  And the chalk can be refilled by way of the air valve!  Never run out of chalk, and never run out of fun!
Brilliant Little Bedtime Conversation Starters
What is the best outdoor chalk masterpiece you have ever made?
Who would you like to spend an hour drawing in chalk on the sidewalk with?