In the figure we have one of the many ways to program the counting of a 4017. The circuit uses additional gates and was found in the Radio Electronics magazine of April 1989.
This electronic Morse Key for telegraph message transmission was found in an American 1980s...
This PWM control circuit was found in an old documentation, but appears elsewhere on this site...
Found in a 90s Radio Electronics, this circuit uses an AD590 or AD592 for remote temperature...