All Toyota Lexus hybrid vehicles do not have a mechanical reverse gear, the direction of the electric motor or motors are reversed to go backwards. None of the CVT gearboxes use belts and variable cone pulleys to change the gear ratios. The front transmission unit has two electric motors, one directly connected to the drive wheels and another connected to an epicyclic gear train and has two functions, 1 to start the engine and 2 to vary the ratio of power between the engine and electric motor. There are some very good videos on YouTube which explain this better than I can.