The necessary cube falls downwards turn of a corresponding lateral side (R, B, L) and is deduced on a front side by operation D, D' or D*2. Operation of deducing by mirror turn of the same lateral side restoring initial position of the mentioned costal cube of the top layer (opposite) comes to an end.
After that operation a) or b) the first stage is carried out. In a case a) the cube has left on a front side so, that color of his forward side coincides with color of a facade. In a case b) in is necessary not only to move a cube upward, but also to develop it that it has been correctly focused, becoming on the place. In figures points mark a place on which there should be the necessary.
The necessary cube is under the central cube.
Result: the cross of the top side is collected
The necessary cube is in the bottom layer, but at the left or to the right of central.
