1. A method of navigation and input comprising: imaging a mark whereby an image of that mark is captured by an imager sensor, determining at least part of the location of that image of the mark in the imager sensor, determining the number of image pixels in which that image of the mark is captured by the imager sensor, establishing a threshold of change in the number of image pixels in which that image of the mark is captured by the imager sensor, establishing a time frame threshold over which such change occurs, establishing whether the exceeding or the failure to exceed those thresholds is intended to indicate an action to be taken within the computerized application, tracking the number of image pixels in which that image of the mark is captured by the imager sensor, generating a signal to the application that an action should be taken based on the tracked number of image pixels in which the image of the mark is captured by the imager sensor exceeding or failing to exceed the thresholds established, and performing the action so signaled.