LEGO 【MINDSTORMS】EV3
Invert Motor Block
Invert Motor Block - Overview -
The Invert Motor block changes the direction of rotation of a motor. When you invert a motor direction, a programming block that would normally make the motor turn clockwise will make the motor turn counter-clockwise instead.
Select the motor (A, B, C, or D) that you want the Invert Motor block to affect by using the Port Selector on the top of the block.