The last day of November

Our yard is full of water. We play and make waves.

The observers. They are watching us.

They have a ruler which can help to meter the deepness of water.

We have some audience here. This swamp is the deepest and the biggest.
Can you see how many centimeters are here?

Here we can see some leafs, branches, our friends' silhouettes and
 a ruler which meters the deepness.

"Here are written the deepness of swamps.
1.5, 1, 0 and 2 look  impressive, because  it is my first scientific discovery."