I am looking for chess problem solving softwares that handle fairy pieces, like Popeye. Except that I want a software where I can create my own fairy pieces, and I want a software where I can change the size of the board. The first thing is much more important to me than the second. I don't necessarily need one software that does both of these things. I can also go with one software that does the first thing and a different software that does the second thing, that would be perfectly fine.

As far as I know, I can't do any of these two things on Popeye. Popeye has a list of about 130 fairy pieces. If the piece I want is not in the list, then I can't use that piece.

I don't need to create complicated pieces, like asymmetrical pieces or pieces that don't move the same way they capture. I just need to combine two simple pieces.