devices having four buttons that may be configured to control scrolling along two axes, such as along the x- and y-axis, along the x- and z-axis, along the y- and z-axis or the like according to another embodiment of the present invention; FIGS. 9A and 9B are a simplified top and side views of a control device according to an embodiment of the present invention; FIG. 9C is a simplified schematic o