zlacker

I wrote a terminal emulator in Forth on my Apple ][ that had different sounding key clicks for different classes of keys. Upper and lower case letters had different tones, and the sequence of digits had rising tones, and certain control characters like return and backspace and escape and punctuation and space all had their own unique sounds, so you could hear what you were typing and know that you typed the right keys when you were typing ahead quickly on a slow 300 baud ARPA TIP connection.

Also each time it beeped the bell it would start at a higher and higher tone rising to a fixed pitch, each starting higher and lasting less time than the last, so a lot of bells in a row would ramp up in tone and shorten out to a high buzz, so they weren't so annoying. Then it would decay back down after you didn't receive any bells for a few seconds. It was inspired by the way of an excited guinea pig squeals for lettuce.

https://www.youtube.com/watch?v=5jfoxSeJzWo&ab_channel=It%27...

Also, the underline cursor floated up and down and up and down in the character cell, so it was very easy to see where it was, and it drew a wavy line in the phosphor as it moved across the screen!