Gengeral Interchanging PAIRs Move
If only the R and U face are turned, at the starting and ending of the move, pairs will be placed in the same shape, no pair will be broke but one pair will be interchanged, and the positions of the other pairs will remain unchanged in the end, which is called "R, U Layer Interchanging PAIRs Move"
Similarly, if the U in the above is replaced by the D, it is called "R, D Layer Interchanging PAIRs Move"
The above is all called "Interchanging PAIRs Move"
As shown on the right is one of examples of "R, U Layer Interchanging PAIRs Move".
As shown in the above example, one of the turns is the U layer as shown on the left, which rotates the U face by a straight angle, but the R layer does not have such a rotation. It is called "Interchanging PAIRs Move Interchange on the U Layer".
The above description can also exchange the R and U letters or directly change the letter U into the letter D, and there are "Interchanging PAIRs Move Interchange on the R Layer" and "Interchanging PAIRs Move Interchange on the D Layer".
Anchor PAIR and Double Interchangable PAIRs on Different Layers
Two pairs are in the same layer and their relative positions are as shown on the left, called "Parallel PAIR"
Parallel PAIR is on the D or U layer and R face turn will not break the arrangement of Parallel PAIR or the PAIR itself, then it is called "Anchor PAIR"
The D layer and the R layer have a total of 4 pairs. If the D layer has Anchor PAIR and the R layer has Parallel PAIR, these 4 pairs are called "Double Interchangable PAIRs on Different Layers". or DIPODL for short.
Replace the above D layer with U layer and use the same name.
Interchanging PAIRs Move of DIPODL
Observe the shown on the left ,R, U layer all have a DIPODL. If do Interchanging PAIRs Move Interchinge on the U Layer, the changes of the edges are all the interchanging of the edge on the U layer as shown on the right between Parallel PAIR and the edge not between Parallel PAIR. The two corners that are not on DIPODL will also be interchanged.
The above description is not only for the R and U layers, but also the above-mentioned R and U layers can be swap or the U layer can be directly replaced by the D layer.