The lower part reminds me of five bar gates, box #tallies or a Chinese #tally, but adding fives to make numerals out of them is neat. As base twenty numerals, with a sub base of five, they go really well with old British counting - what's commonly called #SheepCounting.
The names of the numbers vary from region to region, but I count: yahn, tain, tether, mether, mumph; hither, thither, over, dover, dic; yahn, tain, tether, mether mumphit; yahn, tain, tether, mether, jigif. I find it easier to keep my place counting this way. The rhyme, cadence and repetition also have a soothing effect on some babies, like a #lullaby - which is where the idea of counting sheep to go to sleep comes from.
You could limit yourself to one line at the top to use them for "normal" base ten numbers. I do like how clearly they look like the number they represent.