These gauge images are very nice.
Before the nice Facer guys provided the new progress indicator, using images like these was a good way ( only way (?)) to show progress like info. With the new progress indicator it is now possible to do something like this with just a few layers.
You would need a foreground mask layer which has all of the progress steps cut-out as holes/windows in the layer. And then one or more progress indicator layers sitting underneath it to light up the windows above it as the progress changes.