Making an output go high while another sequence is running

[DaveX]

@Pimpom

I've written a simple beginner's code that works up to a point but I want to add something else. What works so far is that pressing a button causes 4 OUTPUT pins to go HIGH progressively (not in turn) and all four remain HIGH until another (second) button is pressed.

That question almost matches this introdution to a very good tutorial:

@Robin2

When you are new to programming and the Arduino system it can be very tempting to use one of the example sketches and make changes or add bits onto it to meet your needs.

If what you are doing is even a little bit complex this approach will quickly turn into an incomprehensible mess. There are plenty of questions in the Forum that provide vivid examples of this.

Adding bits and pieces will probably seem fine as long as you have the correct image of the code in your head. But as soon as something doesn't work as expected the mental image will be derailed and figuring out the problem becomes a nightmare - literally - late nights, too much coffee and no progress. More bits are added to try to monitor the progress through the code. And those bits themselves start to cause confusion.