Nope as nice as this idea is, it is sadly just inventive straw-grasping. Arabic numerals came by way of Indian Gwalori numerals, all the way back to ancient Babylonian numerals.

This picture shows how the symbols evolved. While it's true that the numbers 1, 2 and 3 came about from pictorial representations of the amount (shown as lines, or sticks) there's zero evidence any numeral representation ever came from the number of angles involved.

When you consider how fluid Hindi and Arabic writing styles are, with sweeping curves and circles, and contrast that with the Germanic looking, runic style that this picture adopts, you can see how unlikely this is. There has also been a good amount of liberty taken in order to get those angles to appear, such as the pointless crossing of the nine, the tail of the five, or the bar of the 7 (a much later addition to the number, to distinguish it from the Latin character Z, although sometimes the number 1). And that extra bottom serif to the seven just looks ridiculous.