Using common sense I know that things move in three dimensions x, y and z. Now, if a thing is moving along x and y at the same time we say that is moving in a oblique direction. Now, I want to know if this is actually what happens at a microscopic scale, I mean does matter really moves along x and y at the same time in continuous motion or do things move along an x direction first and then along a y direction? To make it more clear, does matter moves like going up the stairs or going up on an inclined plane.
EDIT: this doubt partially was born in my mind because of the concept of the Planck length, which should be the smallest distance possible. If that's true than a continuous motion of matter can't exist.