What strikes me when I study these images carefully is the variation in shape of the characters.
Some numerals are solid; others are outlines. A few are made up of almost all straight lines (see the spacy font at the bottom of the right column). Many are all curved lines.
The loops may be round, oval, filled in with dots, crossed by slashes, filled in entirely, or there may be no loops at all (see the black font in the middle of the first column).
Font designers go to great lengths to differentiate their work from what has gone before, but must also retain the essential character of a font family AND fit the individual shapes into that family. If they can demonstrate the uniqueness of their font design, they can patent it. Here are a few recently-patented fonts:
None of these fonts look like fingers held up for counting, or like ASL signs for the numerals:
yet our students manage to learn them the fonts (or hand signals), draw or write them, and use them to represent quantities.
As they gain experience from Kindergarten to Third grade or so, we expect that kids can recognize any Arabic numeral shapes, even when they vary dramatically when hand-written or in decorative fonts. Plus Roman numerals, too.
We'll think about this a bit more tomorrow.
