Hardware conttrol panels historically have used several types of meters. Tcl/Tk widgets have already been written for what I would call 'angular meters'. That is a meter whose needle shows the value of the data it is monitoring through it's angle. A more common meter in the control panels where I work is a 'vertical' meter. Think of this as a vertical rectangle with a tick mark scalen and a needle that shows the value of the data it is monitoring by its height in the rectangle. Here's a snit::widget that is my first cut at implementing a 'vertical' meter (still a few edge issues with tick marks):