When I was growing up, magazines like Compute! had a nifty feature to let you know that you typed in your code correctly. Each line of code in the magazine had a checksum value. As you typed in your code the computer would show you a computed checksum, and you could compare that to the value in the magazine to immediately know if you typed it in correctly or not. Much easier than scanning the entire line and comparing.

Given that there are currently few tools in bits box for debugging this would be an asset to kids typing in whole programs and trying to figure out where they fouled up.