It took me a long time to come up with a secret message, but I am happy with the one i settled on. I used a pretty simple cipher. Bonus points to the player that decodes it first.

I decide to install my messages during my lunch break. The problem was that it meant there would be a lot of people around, but that was part of the fun. it was easy to hide them without being noticed, what was difficult was getting the pictures. I had to use my phone, thus the terrible photo quality.