Tutorial, educational instructor's illustration: attractive and joyful piano keys, keyboard, notes in rainbow colours for easy memorizing, e.g. for kids.
Note that both small and large (for comp) previews are oversharpened by DT automatic algorithm, and the horizontal lines only seem to be of uneven thickness. In the original (for download) all the lines are of equal thickness and there are no halos around clefs and notes.
If you need the picture without coloured spots, or other variations, feel free to contact me (leave a comment via Tools tab).