As a kid I used to do this card game/trick a lot but I can’t remember what it is or how to do it anymore. All I remember is that it used math or counting. You had a certain amount of cards sort of laid out in a circle face down and then other cards are added on alternating between horizontal and then vertical. So a circle of cards with rows going down that alternate between vertical and horizontal. Now using math/counting there was somehow a way to flip cards that end up matching and all your cards you flip end up matching. I cannot remember how this was done. Does anyone know this trick/game?
I don't really know if this is it, but some google-fu gave me this trick. It sounds about the same?