1. Character lumping
Certain kinds of characters are tiny and stackable, and in high concentrations form a solid body.
2. Trick fonts
It’s not a different font, technically: these characters are actually hidden within unicode. So are the characters used to build the next three.
6. 125 spaces
There’s no reason you can’t use most of your 140 characters on line breaks. This works better in clients — the Twitter homepage eliminates multiple spaces.
7. Diacritic overflow
These unicode characters are intended to help render non-English languages. They’re also handy for breaking out of tweet borders.
Use this site to type pretty much anything in ⒷⓊⒷⒷⓁⒺⓈ