While the computer program itself is a creative work, the important factor is that it is being used as a tool in an overall creative process. Kraft is probably very unhappy with their illustrator for not just creating an original maze. There's definite copying - the styling and layout are too close for there to be otherwise, but the creative expression in the original is so minimal that it likely balances the fair use criteria (nature of the work, effect on the negligible original market suggest it is fair use, commercial use counts against fair use.) In the specific case, Kraft's maze is a significantly better maze - also evidence of the lack of individual creative analysis in the original. However, there's very little "creative expression" in the individual maze, as an algorithmic result, the creative expression is in the inputs, resulting in a "thin" copyright - only applying to virtually identical copies. So yes, the maze is likely subject to copyright. "original" boils down to "more creative than alphabetical ordering", and "tangible media" includes pictorial/graphic displays. (There are some exceptions, like for US government works.)
In the US, copyright automatically applies to "original works of authorship fixed in any tangible medium of expression".