Snatwix
Snatwix is a language used to communicate in a school secretly. When teachers ask to see the note it looks like gibberish. Snatwix can be learned easily and memorized within 3 days. Kids use it in the USA to tell people "Important" things. It consists of the regular alphabet but drawn in a different ways. A Standard Teacher will not know how to read Snatwix
"We send each other Snatwix so the teacher does not know what we are saying"