This keeps track of people who viewed the project. While not in order, here is how this works: When you click the green flag, if your username is on the list, you don't get to do anything. But, if your username IS on the list, you can replace a random scratchers spot. Your name will stay on the list until someone else replaces it.
Didn't mean to unshare + reshare I thought it was a different project I accidentally shared.
