Hi Bob,

    Now,  you’re ready for mass production !

    Just kidding, this set is an eye catcher, well done !

    I recommend using strong neodymium magnets underneath each cube to make a sturdy construction.

    For the ground connection, you can use these magnets for contacts. Some of them have small eyelets where you can attach a wire using a bolt and nut.

    Did you use a special earphone ?

    I would love to see a circuit build with this set.