Theoretically, a slashed zero should not have the slash extending beyond the main body of the character, but in practice, especially in sloppy writing (when the

Theoretically, a slashed zero should not have the slash extending beyond the main body of the character, but in practice, especially in sloppy writing (when the slashed zero is more common) it often does. Also when designing a font for someone who has difficulties distinguishing character shapes, small differences like that may not be immediately obvious. Using a reverse slash immediately shows that it’s a zero without any clashes. I think it’s a fairly elegant solution at the slight cost of being a little unfamiliar (although the slashed zero itself is quite unfamiliar to most people).