Wurdle

the keys remember, so you do not have to.

the five-letter word game, typed on a gold typewriter: six lines down one sheet, the verdict struck in ribbon, and a keyboard where every key holds the best thing you have learned about that letter

This is the word game, played straight -- a five-letter secret, six guesses, and the verdicts on the real rule: a letter is green in its own place, ochre if the word holds it somewhere else, and unstruck if the word has none left to give (so the second L of a guess stays grey when the answer keeps only one). What the typewriter adds is where the thinking lives. In your head, a game like this is an accumulating pile of facts -- R is out, E is in but not third, there is a T somewhere -- and most of the difficulty is carrying that pile, not deducing from it. So the sheet keeps every line you have typed, in view, because rereading them is half of how anyone plays; and the keyboard is the biggest thing on the machine, with every key wearing the best state that letter has earned: ivory for untried, ochre for in-there-somewhere, green for placed, and dark and sunk for a letter you have ruled out. A ruled-out letter is the absence of ink rather than a colour, which is what ruling something out actually looks like on paper.

Concepts: constraints, deduction, information.

An interactive you play with one thumb, on Wundr.