Patterns are oriented such as the 2 pairs of corners are C12 and C34. For identification, C12 spin will be identified from C1's, and C34 from C3's. For instance, C1-C2+ and C3+C4- will be C12 counterclockwise and C34 clockwise.
C12 counterclockwise will have both yellow stickers oriented to the observer, whereas C34 clockwise will have both yellow stikers oriented opposite to the observer.
Only the center is yellow.
C12 counterclockwise, C34 clockwise
|R U B' l U l2' x' U' R' F R F'|
C12 clockwise, C34 clockwise
|y R' F R F' U2 R' F R y' R2 U2 R|