If you allow cropping, you can always do this. Suppose the tiles are T1, ..., Tn. The "self-tiling" property means you can tile each Tk with smaller copies of

If you allow cropping, you can always do this. Suppose the tiles are T1, ..., Tn. The "self-tiling" property means you can tile each Tk with smaller copies of T1, ..., Tn. Or, equivalently, you can tile a larger copy of each Tk with copies of T1, ..., Tn. So: pick one of the tiles. Tile it with smaller copies of the tiles. Tile each of those with still-smaller copies. Tile each of those with still-smaller copies. Etc. Now pick a region in the original tile that's the same shape as the thing you're trying to cover. This process covers (the whole original tile, and hence in particular) that region with finer and finer copies of the tiles.