Flip two. Keep what matches. Forget nothing.
The concentration card game — matching pairs, Pelmanism, or simply "the memory game", depending on whose living room you learned it in — has been played with ordinary playing cards since at least the 1930s, and as a boxed set of picture tiles since the 1950s. It's the rare game a four-year-old can win honestly against an adult, because young brains are shockingly good at remembering where the frog went — which is exactly the flip-and-groan moment this version is built around.
Play it solo against your own best move count, take on the shared daily deal to build a streak, pass one phone around the table with the classic match-and-go-again rule, or start a duel: two devices, one live table, same cards on both screens. Free, no ads, no account — and everything but the duel works offline once loaded.