Methods and apparatus to display information via a process control device are disclosed herein. These tools receive, from a finger grouping subsystem, data representing velocity parameters associated with contact points, with the contact points representing physical actions taken by users in interacting with software applications presented on a surface computing system. The attachment device extends through the clearance aperture of the blocking element when the blocking element is in the second position. The method further includes removing the first semiconductor substrate. At least one reflective marker is mounted on one edge of the sash opening to reflect light from the at least one light emitter. m3, are desirable in many applications.