Hmm, Ian, it would be cool if tere was a way to fill a perimeter with a terrain, unit, structure or region. Like maybe with control-space. Because right now I have to build a wall around each of my maps manually just for aesthetic purposes. It would be like the current m, shift-space combo but maybe control-space instead to fill the perimeter. This would also do well for walls of rectangular rooms or fenced-in compounds.