The program Nim Game XL allows to play a wide variety of Nim games, from the simplest one with only one heap up to complex games with dozen or several dozen of heaps.
Nim games are strategy games for two players (the program can replace the other player so you can play alone). We have at the beginning heaps (or rows) of objects (which can be matches, tokens, coins ... and why not bricks ...), and one after other the players must remove one or more objects in one heap, until there are no more objects. You can decide as end game option that the one who gets the last object is the winner or the loser ... They belong to the games called "impartial games" where you can find a winning strategy by calculation.
An example of Nim game is Marienbad, there are 4 heaps and objects are matches. You can play this game with the program Marienbad, available on Android market, or with Nim Game XL (you have just to take the defaults).
You will find in the game help explaining how to use the program and to calculate the winning strategies. If there are not too many heaps, you should be able to do calculations mentally with a little practice. For more complex cases, the program offers to each player a worksheet to write numbers and do small operations.
Adapting for Android 13