1. A method for determining motion in two dimensions, the method including the steps of: (a) illuminating a surface with light from a laser; (b) receiving the light in an array of pixels arranged in a plurality of rows and columns after the light reflects from the surface, wherein the light includes a speckle pattern and wherein the surface is moving relative to the array, and wherein the array includes a first arm and a second arm and at least one pixel-free region between the first and second arms, the pixel-free region being larger than a square having sides equal to the average pixel pitch within the first and second arms; and (c) calculating movement of the surface in two dimensions based on spatial and temporal gradients of output from the pixels in the array.