I noticed that O and 0 don't look different. Although there's a big table on the page showing all the letterforms and numbers where the 0 has a slash, the demo

I noticed that O and 0 don't look different. Although there's a big table on the page showing all the letterforms and numbers where the 0 has a slash, the demo has it with no slash. I'd fail it for programming if O and 0 are identical.