Uses what I call "The Calculator Cipher". It works like the letters on a flip phone, but the ordering is like that of a calculator. Left backspaces, and Right clears. 7 8 9 ABC DEF GHI 4 5 6 JKL MNOP QRS 1 2 3 TUV WXY Z 0 Space
Decoder https://scratch.mit.edu/projects/93385469/