Everybody knows this!
The expression "Knock on wood" is usually used in the hope that a good thing will continue to occur after it has been acknowledged.
For example, someone might say: "The rain looks like its holding off, knock on wood", or "Knock on wood, Im much better now."
"Knock on wood" features different types of wood with different high quality sounds!
Knock / Touch the iPad and different sounds (with each different wood-type) will appear!
From now on you can knock on wood everywhere!
- Different wood types
- with different knock-sounds
- helpful information about this superstition
- tweet everytime you knock on wood! (to your twitter account!)