I too can't read some of the symbols in John D's HTML. I too have a Mac. The
font set is simply different between the two -- for example, I have
characters in Times on the Mac that will not resolve on the PC version.
WebAssign (the homework service) solves this problem by adding GIFs of all
the Greek letters and other standard math symbols that aren't in the same
place over various font sets.
Theoretically, this should all go away when using the latest iteration of
the new international 65K character fonts called Unicode (I think that's the
name). I think that OS X on the Mac and Windows ME supports them, but I
don't know.
For what its worth, I can't read the PDFs that John posted. The text was
rendered as a graphic and the resolution isn 't high enough or something in
the encoding went wrong. Usually I can sort through what John is trying to
get at, so I don't worry too much.
Finally, I have wanted to John and Bill Beatty the ASCII award, for
excellent use of text pictures and aligned formulas. I need to do for my
students sometimes in email, and I am amazed at how good a job they do.