I somewhat remember some kind of hidden sand bags or something? But I don't remember any details, it was many years ago
really sorry for bump, but i think i have found another easter egg: also, here are some stuff that i found.(they might be not easter eggs, but i found them to be interesting:
Yeah, the confucius, the campfire and the neilogical related note are easter eggs. The upside down tree and the toilet signs are just decoration