Computer Science Fun with Excel

There are a lot of pretty cool things one can do with Excel. Today I stumpled upon two of them at Hacker News:

First, Felienne has implemented a Turing Machine in Excel which basically means that one can process "every possible operation" in Excel, too.

The second one is a ENIGMA machine implemented in Ecxel as you may see in this video:

You can download the sheets on the respective pages.