From now on my Piano Animals for four and six hands can be ordered at Donemus:

Piano Animals Four Hands to be ordered at Donemus
Piano Animals Six Hands to be ordered at Donemus

As it has been written in the preface:
The purpose of this book is to compose pieces for four hands piano that are not very difficult to play. The pieces have a very logical structure that is easy to memorise, although they seem te be more complicated.
These pieces can be played by beginners after two or three years of piano lessons, as long as they have some sense of rhythm. They are intended for everyone with a playful spirit, independent of age. They might also be interesting for more advanced students because of the challenge to play exactly together.
It could help to listen to audio examples. You can hear them via the link below:

The picture below is from Pinterest, if anyone disagrees because of Copyright I will remove it.