Here is a curiosity: an archive that can be constructed using a single GNU tar invocation, that is extracted in 8 distinct ways depending on what tool you use.
It creates an archive hardest.tar from three files file ./file empty in sequence, where file is repeated so that GNU tar stores the second one as a hard link, and empty is empty. Exploiting the unique path of the second entry, the hard link is renamed to café. This triggers tar to create a pax header to store the file name as UTF-8. We add a size=512 record to the pax header, which overrides the default size=0 from the hard link. The value 512 is not a coincidence: it is exactly the size of a tar header.
Visually, this archive has the following structure, with two basic interpretations based on whether a hard link can have a size or not.
