The autoharp is a relatively simple string based instrument which uses a series of bars with stops on the underside, so that when you press the button on the top section these stops are placed upon the string therefore deadening the sound of certain strings providing a set chord. (These stops can be seen in the beginning of the video where the camera can see into the working elements of the autoharp)
Whilst the instrument is relatively simple to operate and play, its very nature means that it would be hard to accompany with any other pitched instruments during improvisation as its possible for the user to jump from one end of the scale to the other between two separate chords.
This article (
Article source here) explains some of the tunings that are used witihin small 'cigar box autoharps' which the author makes and also looks at some of the dimensions and problems that he has come across during his time making the autoharps.
The video above shows the method used by the creator of the video to create a 'cigar box guitar'.
The video is an interesting example of the ways in which it is possible to adapt the basic principles of instruments and using found materials to create playable instruments. Whilst I doubt the 2x1 neck offers a great level of playability and sound quality it shows that you can break the standard rules of instruments using the very best quality materials and techniques to provide a working instrument that can produce a relatively toneful sound.