Miracle Pebble

Congratulations! You solved all my puzzles!
You're great with pebbles, and I'd like to reward you for your efforts with a little gift.
Will you accept it?

Here, take this!
This pebble only looks ordinary. But it contains great magic.
All summer you showed what the world around us looks like in the language of stones. And these pebbles will show how you look!
Just don't be surprised - every moment something subtly changes in us, so your appearance will change every time you use the pebbles.
Take them, they are yours!