The game continues with the original shape used to start the game.
 
When a shape-game is started, a snapshot of the shape is stored with the game. Changing the original shape will only change the new version of the shape, older games with the same shape-id continue undisturbed.
When you view the shape following the linked -icon, a comparison is made and the differences shown on the shape-view page.
 
The thumbnail of the -icon is still showing the original snapshot the game was started with, while the shape-page for the shape-id might show a different shape then (with the differences).