Switches appear as a yellow block with a piston and a red button on top. When they are landed on, the button is pressed down onto the box.
Switches can be pressed when the teeny hero walks into it. If the player jumps into a switch, it will also be pressed. They are necessary to complete the level, usually because the blue blocks are in the way of progression to the top of the level. When switches are pressed, nearby blue blocks will move into their programmed places. Switches will never come back up, unless the player dies or restarts the level.
A glitch that always happens is that when a switch is up and in between two other blocks, the two pixels on either side of the switch will be the sky blue color, even if everything around it is a different color. It is unknown whether this is an actual glitch, however.