Two transparent 3x3 grids of squares are overlaid. Grid 1 has a black outer border (all outer squares are black, the center square is white). Grid 2 has a black diagonal running from the top-left corner to the bottom-right corner (these three diagonal squares are black, all others are white). If a new grid is created where a square is black only if it is black on both Grid 1 and Grid 2, which squares on the new grid will be black?