A photo of a <a href="https://en.wikipedia.org/wiki/Miracle_Piano_Teaching_System" class="extiw" title="w:Miracle Piano Teaching System">Miracle Piano Teaching System</a> keyboard.
<a href="//commons.wikimedia.org/wiki/User:Gazebo" title="User:Gazebo">Gazebo</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>