Showing the usefulness of that, back around 1985 I was in a training session at Unisys and the instructor told us about his time as a programmer in Vietnam during wartime. He was part of a group that modified software for artillery fire control systems in the field, and each time one of the soldier programmers got orders to return home he would leave an easter egg in the code. A few days later a message might pop up saying, "Drinking a beer at home watching tv, wish you were here??" or little things along those lines. The instructor said one guy, however, went into the code and globally replaced variable names with combinations of 1, l, 0, O. Since the 1/l and 0/O were displayed identically, the programmers didn't find the prank funny. Our instructor said as he traveled the US training groups, he hoped he would find the guy. 10 or 15 years later he was still more than a tad angry. All for lack of slashes and serifs. Incidentally, living in Austria I was surprised to see ones commonly written looking nearly like upside down Vs. Mike Markowski On 4/13/20 8:38 AM, Clem Cole wrote: > FWIW -- I still slash both zeros and sevens.   I was probably 12 when I > was taught that trick, plus the print head of an ASR33 slashed zero's > and 1, l, 7 were all distinct. So sat the time, it seemed cool and > advanced.  Then it just became a habit, and as we know, old habits are > difficult to change and frankly, I never saw the reason to stop.  My > handwriting is a bit of a mess as it is, so anything I do the make it > clear has always been considered a good thing by people around me.🤔 > > On Mon, Apr 13, 2020 at 7:31 AM David Barto > wrote: > > Yes. When I took my first programming class at UCSD they > specifically went through the numbers and alphabet showing the mark > up and being very careful to go over 0, 1, 7 and O multiple times. > I’ve stopped slashing my 0, and I still slash my 7. IDK why I > stopped the one and not the other. > > A long time ago, in a universe(ity) far far away. > >         David