Triple negations

I'm packaging Ruby's PDF::Writer module for Debian - It is a simple module and (almost) ready for upload. But anyway, it carries some issues I had to bring to debian-legal's attention, mainly, five files licensed under Creative Commons licenses (specially two of them, which are under its NonCommercial variant - clearly non-free), so I'm repackaging the .orig.tar.gz into a +dfsg version.

But I know I'm a lazy and sometimes stupid bum. Even more, the package will be group-maintained by the pkg-ruby-extras team, so we must be as careful as possible not to forget to remove the non-free material - To remove two scripts, and to replace three images with free equivalents I just made. But hey, tell me if this does not feel ugly to you. At least to the bits of you who learnt human grammar:

clean::
	# Make sure we strip out non-DFSG demo files from the orig.tar.gz
	[ ! -f demo/qr-library.rb -a ! -f demo/qr-language.rb ] || false 
	[ $$(md5sum images/bluesmoke.jpg | cut -f 1 -d ' ') == 0586eca5af7523ab871609eceb44724a ] || false
	[ $$(md5sum images/chunkybacon.jpg | cut -f 1 -d ' ') == a000b1917142ce332fd3474f0722cd6f ] || false
	[ $$(md5sum images/chunkybacon.png | cut -f 1 -d ' ') == 927feec1cbbf23c4d89a4a5ad88e6d0f ] || false

Triple negations. How nice.