Learning how to see the structure of a base in 'grid' form does wonders to your attack knowledge. Knowing the ranges of these buildings can be important in a war attack where ☆s matter. Thanx Kraitok for sharing ;-]
On a side note, I tap a building on my base and slightly move it. When it shows red I remove my finger from the screen and it stays where I left it red. If you look closely you can see what I call the 'footprint' of the building. Walls have a 1 tile footprint where town center has a 36 tile fp. Wikia has a ton of info on the game, including many a building's ranges of fire/spawn as well.
