Click on the blue cards outside the box to place them into the box, one after another from left to right.

When enough cards disambiguate a choice, you will start to see white cards at the top left appear.

At any time, you can click on one of the white cards to complete the topic selection.

Click on the last blue card added to remove it from the box and so on.

If you click on a blue card to far to the left, all cards may be removed if the sequence of cards left has no meaning.

To remove all blue cards, either click on 'Clear' button or click on the first blue card inside the box.