Wow, ... it's working.
Mr George, Thank you very much.
...
In connection with notes about sound events like signal to user that something is wrong:
some PC has a small routine which produce beeps when user press a key. That is sign to user that key is pressed and no need to watch out on screen to check is key for sure pressed. This is reason for sounds as warrnings not good.
Other reason is that some people in rooms start making nervous (mad!?) from these sounds and many beeep, blurp, boing ....toeing ... couldn't be nice solution for some quit working rooms; just clicking of keyboard is enough for 8 hour of working time.
LED flashing is discretly warning to user.
About electric shock for user who are making oft the errors: why not an automated big hammer: for first small errors a small kick at fingers, for bigger error hit at head, ... etc. ;-)
Eh, girls and boys ...