Run

A run is a series of at least 3 cards with successive values.  

Things that count as a value are the card number, the number of sides on the shape, color, and the card's letter.  Only one value need increase at a time to count as a run.

You may "unplay" the most recently played card.

Try for a high score.  Longer runs score higher.  Using the same value many times in a run scores additional points as well.