Clean room? That means nothing. Adobe is simply going to sue ArtCraft for anything and everything... trademark, copyright, look-alike, and whatever their greedy lawyers come up with... figuring that ArtCraft does not have a bottomless pit of money to defend and that Adobe will "win" by default.

It sort of reminds me of when in 2003 the SCO Group sued IBM for billions of dollars, alleging that IBM took trade secrets and joint UNIX code and donated them to Linux.

Then again, if ArtCraft puts this into the public domain and basically has no money, Adobe will have a hard time keeping people from using it.