Raw square wave instrument for Music Studio?

I am looking for an instrument with a pure square wave for use in Music Studio. I did the IAP to get a bunch of instruments, but alas no square wave. How can I get one?

There’s the old instrument sharing forum thread https://www.xewton.com/musicstudio/forum/viewforum.php?f=10&sid=504a0b3c00f503cebf21726a981584f5
but nobody posted a square wave there.

So I would suggest downloading a wav file of a square wave (or better, a whole set of square wave samples with different keys) from one of the many free sample download websites, creating a user instrument in Music Studio, importing the wav sample(s) onto the right base key and tapping the Auto button.

See https://www.xewton.com/musicstudio/doc/?id=14