Today I heard from someone who was complaining that Arial is an abomination. I'm not the biggest fan of Arial either, but I'm superstitious, and most of my successful grant proposals have been written in Arial. So I keep using it. In general I don't like sans serif type, but somehow they never seem to work in grant proposals for me. Manuscripts, that's another story. There I've had luck with a mix of stuff. But back to Arial. Arial was based on the much storied Helvetica, designed in the 1950's. Arial was a knockoff and was one of the fonts bundled in Microsoft Windows 3. While there are differences when you compare both fonts side by side, to me it is very hard to tell, and I bet the same for most folks.
So here's a challenge. Download the linked PDF file and (without cheating) tell me which paragraph is in Arial, and which in Helvetica.