OLL15 (Knight Moves shape)

(R’ F’ R) (r’ F’ r U) (R’ F R) (horizontal center line & a colored ULB)

(r’ U’ r) (R’ U’ R U) (r’ U r) (horizontal center line & a colored UFR)

It is smooth if you use Michael Trigger for F’.

As for (r’ U r), I use my left index finger to turn U, pushing ULB piece.