What i meant about the hexagon is that the bottom white line of the hexagon should be parallel to the bottom of the world map but it isnt it is at an angle.

The waves somehow time travel when they reach the boundaries.
The cables were created in a way that they seem to link with each other but they not.
Maybe there were transmiters at the extremity of a cable on one era which emit to a receiver on the extremity of another cable on another era.But since they were underground people other than Hyne donīt know it.
Mybe shumis possessed by Hyne created them.
Oh come on you gotta be able to come up with something better than that.
Also you said that you could go through time in the Balamb underwater train tunnel but you said that no one would go through there because of the risk of getting hit by a train. What about when it was being built?