For those who need more instructions of SCm:

 A story of the noble art of playing violin

For your further study of SCm and ACBM I am asking to read the following story:
There was once upon time a  man who went to a music shop:
– I want to buy an instrument with a guarantee of a good sound, he said to the salesman.
– We sell two kinds of instruments and I-pods. A full sound guarantee follows only i-pod. You just press the button here and you hear immediately if it sounds to your satisfaction. A written guarantee follows. But we also have guitars and violins. To the guitars we can give a kind of sound guarantee, but no guarantee to the sound of violin. 
– How works he sound-guarantee for guitars?
– Look at the tiny brass ribbons at the neck of the guitar? the salesman asked and continued: If you press down a string between certain demarcating ribbons and at the same time touch a string with the other hand you get the same pitch at each ribbon respectively. Of course provided that the strings are pitched and that you touch them with equal force. If you buy an instrument we can tune it for you.
– I would like to take a look at the violins too, said the customer. I think that the violin’s power to affect a listener is greater.
– I agree. But we can’t guarantee how your play will sound. As you see, the neck of the violin has no ribbons to demarcate where the player should put his fingers to elicit a sound he desires.
– How do I know where I shall put my fingers to get a sound I want?
– You know it by listening. The player hears the tone he elicits at the moment and moves his fingers either up or down in other to get a higher or lower tone. You need a feedback all the time.
– It sounds difficult, said the customer. A guitar seems to have a kind of guarantee to produce a desired sound.
– Yeah, said the salesman, even a deaf person can play guitar. He just need to follow the notes. If you roll and scream you sound impressive.

The interaction in SCm could be compared with the ability of the violin player let the signals from the discussion parter to steer its means of expression: his voice, his facial expressions.

Our story does not tell what the customer bought.