protected override IEnumerable <IRenderable> Render(WorldRenderer wr, World world)
            {
                var xy  = wr.Viewport.ViewToWorld(Viewport.LastMousePos);
                var pal = wr.Palette(TileSet.TerrainPaletteInternalName);

                foreach (var t in power.CellsMatching(xy, footprint, dimensions))
                {
                    yield return(new SpriteRenderable(tile, wr.World.Map.CenterOfCell(t), WVec.Zero, -511, pal, 1f, true));
                }
            }