I've been working on a card game for many many years, inspired by a Scientific American article that I read in my teens about a game called "Undercut", which doesn't even show up in google now as there have been subsequent unrelated games called Undercut.

Regardless, last year I was working on it a bit more and I came up with an interesting theme for it - that it's a game about the piano duels of 1800 between Beethoven and Steibelt. Each round you each secretly choose a card that has a theme and reveal them. If you correctly predicted the theme they pick, you are able to improvise around that theme and impress the audience.

So today's idea is an aspect of this dueling game, where I try to lean harder into the new theme. Currently you each simultaneously choose a card, and how well you respond to the theme is based on how well you predict. But in a game about improvisation you should also be able to use the cards in your hand to put together a sequence that can recover from a shaky start.

Currently you have a hand of five cards and a layout of five cards on the board in front of you - every turn you play a new card and recover your oldest card. So this new mechanic allows you to go temporarily shorter on cards by playing additional cards on top of the initial choice. When you recover the original card you also recover the cards you laid on top.

I want to capture the feeling of improvisation, so the themes the opponent plays have to be varied enough that you can't just plan around them. This isn't a fully formed idea but there are two aspects to the themes currently: the number of notes (between one and five), and the type of notes - the length, where they are on the scale, etc. Currently the latter is unused; the only important part of the game is the number of notes. What if the "improvisation" bit involves the latter; trying to use your cards to construct a sequence that matches the type of notes played by the opponent?