I made this CardTrick back in 2006, at a time when it would have been predominantly accessed via a desktop computer (and not a smart phone).
On a desktop computer, as the mouse hovers over any card, the whole "row of cards" is highlighted to give clear indication of which row that card belongs to and to imply that the whole row will be selected upon clicking.
On a smart phone, this hover event probably never occurs.
My current idea, to address this, is to use setInterval, so that this hover-highlighting-of-rows happens automatically in a repeating cycle until the user picks a particular row. However, I'm interested in your thoughts regarding this idea and am open to other suggestions for emphasizing the rows to be selected.