[slig]

Hi again Oliver! Just got your email and I'll reply there you tomorrow as well. Thanks for the feedback.

>The grids cannot be solved by themselves. Some external knowledge is required

I introduced this kind of feature in another custom made puzzles, such as one about blood types ("the universal donor is ...") and I got a lot of praise for it and I thought it could be extended to another themes. But I can see that it might be too broad and uninteresting. Will revise this.