It was a game for two people. It was NOT the capturing boxes on a square grid of dots game.
You drew a pyramid of circles and then took turns capturing a circle by writing your initial in it.
If you captured a certain pattern of circles, you got to take another go.
What I can not remember is what the pattern was. Was it a whole line of circles, edge to edge? Or was it enclosing an area of circles? Or was it something else entirely?