To answer this question I made a script to find all possible combinations of lines that could form a digit. I used the LED 8 (Like on a VCR) to base all possible numbers off of. There are 128 possible lines, but obviously some work better than others. To that end I decided only symbols where the lines had neighbors should be allowed (thus a line at the top and an o at the bottom are out of the question). I also decided that it should use the full height of the space provided since all other digits do as well. From here I made a little picture of each symbol.

Check them out:

(Note that some don't qualify as possible digits because not

*all*lines connect together, such as 0110110, 1011010, 1101100)

Now then, which two would

*you*consider unique enough to use as two more digits? heh