use a regulated current source to light them, wire them in series and short out the segemnt you want to be dark.

<!-- Begin schematic: In order to preserve an editable schematic, please
     don't edit this section directly.
     Click the "edit" link below the image in the preview instead. -->

![schematic](https://i.sstatic.net/lkLti.png)

<!-- End schematic -->

 you can possbli use a buck-boost converter to make the 30V if you don't already have a suitable voltage.