Once again, the objective is to replace B by A (see Fig. 16). Observe, from Fig. 17, that C will replace D in the process - it's like rotating the bottom middle cube 90 degrees anticlockwise. Starting with the Cube in Fig. 16, we apply the following formula: B-  R-  B+  R+  B+  F+  B-  F-.

Note that it may very well happen that the cube which is to be placed at the bottom middle is already found in the second row but at the wrong place! This is really raging since you have to displace it first and then apply the formula...

If your cube is now be looking like the one in Fig. 18 below, you know it's time to buck up and get ready for the third row!