My name is Rozemarijn. I invited my friends Eleni, James, Helmut, Chiara and Pierre to participate in a fun game since we are all on Christmas holidays.
For the set up, I asked each one of them to write a message on a piece of paper, then fold it and place it in a jar. The message is composed of a couple of letters and I explained to them how to derive them. We all followed the instructions, including myself. Then I unfolded the pieces of paper to check if everybody followed my instructions correctly.
These were the 6 messages:
FW
ZT
PK
KX
JN
MC
One of the messages looked a bit weird. After a quick online search, I confirmed that one of my friends did not follow my instructions correctly. What should (s)he have written?