If you view in firefox (linux) with encoding set to Unicode, you will see that there are two unknown characters where the = sign should be after $pi. Same for the chomp line too. However $circuit is followed by an ordinary equals sign.

Are you using a non-English environment that uses a front end processors i.e. for Chinese or Japanese?

If your screen shows an equals sign after $pi then you are not viewing in a western character set.

It would appear that you inserted one or two double-byte characters. Viewing in Unicode the double-byte equals sign in an unknown encoding shows up as two inverse question mark bullets. Viewed in MacRoman it shows up as two capital angstrom a's (A with a circle over it). Please tell us more about your browser, machine, OS, language. Wierd that you have a good equals sign later.