Plainim is played on a checkered board by removing or adding chips. There are just a few rules.
On a single move, one may only add/remove chips in a single row.
At most one chip is allowed per square.
One may only add chips to the right of a chip being removed on the same move.
The one to remove the last chip wins.
To perform a move click on squares (in a single row) where you want chips placed or removed (see that you confirm to Rules 1-3).
Then press the button "Make Move".
This is the latest among various incarnations of Nim. Each column represents a binary digit.
Each row represents a heap. This variant is the simplest in that you are explicitly given a binary presentation of numbers.
All that's needed is to see that after your move only matched digits are left over. This variant is on a preschooler level.
Plainim misère, is only a little different: the player who removes the last chip loses the game.
Reference
R. K. Guy, Fair Game, Comap's Explorations in Mathematics, 1989