Quote Originally Posted by monroeski View Post
You could always code with torches. Same basic principle as with the colored wool, but you're going to be needing to place torches no matter what so you may as well use them for something other than light.
I believe there is an even better way. Text! Just post a sign and write what the tunnel is going to, or what cardinal direction. Albeit, it is slower to read, but could contain more information then a simple color coordination.