Sorry, the save got corrupted, and then life got busy. Old file had twelve bottle-spawner, one land bottle/shell spawner, and two sea bottle/shell spawner bottles. One of the former and one of the latter was a map; don't know if the map parts count, but the bottle spawner bottles don't seem to.
On having to back up to a previous save, I still have four of the bottle-spawner bottles, but currently 5 underwater bottles (and a heck of a lot of shells!) including an Extraordinarily Unusual bottle with a riddle - I'm still trying to figure out how to find out what the riddle says, the bottle just reads 'This bottle contains a riddle. It appears to be related to an island.' - and a map piece (only one in this file). I have a complaint about the designated hitter rule, the beeper message, and one about tying a bottle to a pigeon's leg (new to me). I now have at least one bottle from each of the three underwater bottle/shell spawner levels, and one from a premade site. Will work on it some more this weekend, I promise.
