I've been able to find plenty of info about acoustic instruments that create sounds close to sine-waves, and I understand that sounds approximating square, triangle and sawtooth waves are produced by different types of acoustic instruments.
Are there any acoustic instruments that produce sounds very close to pure square, triangle or sawtooth waves? (The kind of artificial sounds produced by primitive electronic synthesis.)
I understand that these sounds are easily created by electronic synthesis, and why this is this case.
Suggestion of sounds produced using extended techniques are equally welcome (eg. "excess-pressure-grinds" on bowed strings; multi phonics on winds…), as are examples of mechanically produced (but acoustic!) sounds.