Square-root

Mommy, mommy, what is the square-root of 4 ?
2.
what is the square-root of 81 ?
9.
You are a smart mom. What is the square-root of your hair ?
Square-root of my hair? What is it ?
Your head!
Then what is the square root of a light bulb ?
It must be a lamp ?
Hahahaha, it is Thomas Edison!

2005.3.15 海滨漫步(二)