The project below starts with a single Square sprite that has three costumes—Empty, X, and O—plus an X's turn? variable and an empty makeBoard block. There's also a demonstration when I am clicked script that clones the sprite; try it to see how clones work, then delete it once you understand what it does.

Your job is to turn this into a two-player game of Tic-Tac-Toe: fill in makeBoard so it creates nine clones of the square arranged in a 3×3 grid (the costumes are 50 steps square, and remember to hide the parent sprite when you're done cloning), connect the green-flag script to the setup script below it, and then write a when I am clicked script so that a clicked square puts on the X or O costume depending on whose turn it is.

Your work autosaves (and you can use the Save button); earlier versions are available from the Revisions dropdown.