The dodgy greengrocer and the composer client

A game for kids teaching the to compose music. All we need to know is the 1st bass note. For this defines the musical scale or key ie the set of the allowed 7 notes. For example the song To Megalo Mystiko Mou - Kapnisis: 1st bass is C, scale is C minor ie the set with elements the notes C, D , bE, F , G , bA , bB. Music even at its most involved moments uses the simple rule 1, 3, 5, 7, 9, 11, 13 intervals or notes with respect to bass. For example on the song above when bass is G, the harmony chord is G bB D F, (all these notes are played at a nearby moment in time. Therefore greengrocer named G is selling Gabbages, Brocoli, D....., Flowers, A...., C....., E..... The buyer ie the composer decides which ones to buy and use in the composition with aesthetics as a guide. (Public domain, game conceived while playing with fun the piano with Vicky and writing in her notebook.