Greenguy,
I like the way you are thinking.
Here are my thoughts. As previously discussed amongst us here on this forum, any rendition of a triangle within a circle is slowly being accepted as a symbol that can be used to identify us among the others. Your avatar, Ranger's avatar and the logo I used for my book, all use some form of a triangle within a circle. So, it would be conceivable that some form of those images within a mural would post who or what you are.
Establishing a colour code such as you have presented will work if, and I mean a big IF, during the times of plenty we in this community share the colour code with others of the same stripe. Blue = Water. Green = Food. Yellow = Fuel. Red = Power. I am not sure that is what you had in mind. But if you want others to understand the message, some form of codification (standardized code - universally know) must be established ahead of time.
On the Opsec side of this equation. I have two concerns.
1) You are the land owner wishing to trade barley or wheat. You use your barn mural to "advertise". It is a harsh winter and a band of travelers are passing through. They are short of feed for their horses/livestock. Time has passed and the colour code has become well know by those who have survived (whatever the event was.) They know you have or had feed, enough to paint it on to the side of the barn. They are desperate and they are armed. They come in the middle of the night, after staking out the farm for a week to learn your security procedures. They out number you. They are more desperate than you. By morning they have all that you once had. This is a common type scenario that most fear in a post SHTF or WROL type world.
2) Second scenario. You and yours have been driven a nomadic existence. Although, protective of your own you are not known to be of a marauding nature. You come upon a remote farm/ranch/village. The fly banners and have murals painted that you understand to mean they have water and food a plenty. You and a group of yours goes forth to trade for food and water. Only one little problem, this community uses the code to lure in bait. They slaughter to trading party and then send out a patrol of raiders who slaughter or enslave the remainder of your group.
Not meaning to be a fear monger, but from an Opsec point-of-view.......you have to be ready for all possibilities
In general, I do like the idea. For a starting point of networking and developing a loose method to communicate I see merit in pursuing this thought process. From an Opsec standpoint, we should all be thinking about and developing SOP's to handle this. And not just from the two scenarios I wrote above.
Please, post your thoughts on this. The more we discuss this now, the better prepared we will be in the future if/when we have to deal with this for real.
Mountainman.
