A square wall is tiled with $400$ small square tiles of two colours, red and green. The outermost layer of the wall is tiled with red tiles, the second layer from the outside is tiled with green tiles, the third layer is tiled with red tiles again, and the fourth layer is tiled with green tiles again, and so on. Which colour of tile is more on this wall? How many more tiles are there of the dominant colour? 
Overseas Competition->Knowledge Point->Word Problem Modules->Questions Involving Squares->Solid Squares