After launching the application, you will see the balls in the left and right columns.
You have to sort the balls so that all the red ones are in the left column, and the blue ones are in the right.

But there is one condition that greatly complicates your task: you have to sort the balls blindly, from memory.

Try to remember the location of the balls and click on the button at the bottom. After that, all the balls will turn brown.

Click on the column, and the top ball from it will move to the bottom button.
Then click on the column in which you want to place the ball. The ball will take the top position in that column.

You can peek at the current location of the balls at any time by clicking on the bottom button. But each time you do this, your points shown at the top of the screen will be halved.

After you sort the balls, the game will start over.

You can restart the game at any time with the upper right button.