The hardest stones, by degrees, give way to the touch of air.

The hardest thing is take-off. Once you have it in the air it's not so bad.

Look at little Johnny there, / Little Johnny Head-In-Air.

You have the sun, you have the moon, you have the air that you breathe - and you have the Rolling Stones!

With the stones we cast at them, geniuses build new roads with them

The hardest thing to see is what is in front of your eyes.