Most people use the Super Mario Maker to, well, create Super Mario game levels. [Robin T] decided to try something a little different: building a working calculator. Several hundred hours later, he created the Cluttered Chaos Calculator, which definitely lives up to the name. What this Super Mario level contains is a 3-bit digital computer which can add two numbers between 0 and 7, all built from the various parts that the game offers. To use it, the player enters two numbers by jumping up in a grid, then they sit back and enjoy the ride as Mario is carried through the process, until it finally spits out the answer in a segment display.
It’s not going to be winning any supercomputer prizes, as it takes about two minutes to add the two digits. But it is still an incredibly impressive build, and shows what a dedicated hacker can do with a few simple tools and a spiny shell or two.
[Robin] explains the whole wonderful creation in a long Reddit post, detailing how he used the various mushrooms and bouncing parts to create a binary converter, four adders, an integer divider and a segment display and decoder that outputs the answer. He also put together a huge diagram that explains the logic flow (click for the larger version, but beware; it is about 6000 pixels wide).
He also covers some of the problems he found, such as how he was only able to do 3 bits because of the limitations of the game creator, and how he approached debugging this monstrosity (spoilers: he implemented checkpoints so that he could trigger parts of it and not have to wait for each test).
Thanks to [euqinimod] for the tip!