The music puzzle and coloring books by Katharina Apostolidis have become a standard part of the repertoire in music schools. Children aged 5 and up learn about the world of notes and note values in a way that is appropriate for their age. The small learning steps are complemented by many repetition phases that gradually increase in difficulty, allowing the knowledge to be deeply anchored in the children's minds. The editions are completely versatile and therefore suitable as a supplementary resource for any school and for any instrument. For the treble clef.