I noticed today, while experimenting with TeX, a missing space between consecutive @'s :
@ @ @ @
\bye
The dvi output, after interpretation by the TeX program (on the command line on linux) shows : @ @@ @ (there is a missing space between the second and the third @). I observed the same output with pdfTeX but not with latex. Why is that so?

@characters after compiling withpdfTeX– Apr 16 '17 at 12:00texanddvi2tty: Four equally spaced@characters! – Apr 16 '17 at 12:18