This project is a simple test, using a cloud variable. I've come up with this, because we've had problems with a more complicated project. To test, you need two people using Scratch, on two computers. - Both load this project - One player holds the space bar key down and moves the mouse left and right. The cat should follow the mouse, and the other player should see the cat move too. - Now the first player can let go of the space bar, and the second player can hold it down. Now on both screens, the cat should follow the movements of the second player. - If both players hold down space... not sure what should happen. (In practise, both players just see their own mouse position.)
To make this as simple as possible, this project just uses a single variable. Also, I've put a wait of 0.2 seconds in between each cloud variable set, and read, because https://scratch.mit.edu/discuss/topic/12949/?page=43#post-3419243 says "after setting a cloud variable a project must wait 100ms before setting ANY other cloud variable, not just the one it's just set". (Perhaps the wait could be shorter... 0.1 seconds... and perhaps I don't need it between reads... but I'm just trying to get something working reliably here.)