Reverse

Reverse (リバース) is black block with R on it, that can be found at Special Stages and Bonus Stages. By simply touching it, the block is namely able reverse the camera rotation direction by touching it, which can become useful to get to the other direction. It is first seen at Special Stages of original Sonic the Hedgehog and later repeats the role in Slot Machine themed Bonus Stage in Sonic & Knuckles.