Let's find out. ls | od -a reveals:
Doh! Missed that space after the filename extension. (Thanks to Edgar Holmann & Tom Ivar Helbekkmo who posted to this thread back in 1990.)
UPDATE 1: See also Zhitao Zhou's Can we believe our eyes? which examines two "hosts" files in %SystemRoot%\system32\drivers\etc caused by malware replacing "o" (Unicode 0x006F) with a nearly identical Cyrillic character (Unicode 0x043E).
UPDATE 2: Delete a directory with a trailing space in its name
UPDATE 3: These files both seemingly have the same filename and, though lacking file extensions, are identified in the "Kind" column as Word documents (DOC and DOCX, respectively):
Is there some kind of metadata/extended attribute magic going on here to allow this? Nope - just that durn trailing space again:
/nix | Jul 14, 2006