Spotting patterns

You recognise your mother's footsteps before you see her. You know a song from its first two notes. You can read a friend's terrible handwriting that a stranger couldn't decode at all.

All of that is pattern recognition, and you do it constantly without trying.

Programming asks you to do something harder: notice the pattern consciously, then describe it in words precise enough to hand to a machine.

To describe any pattern, answer two questions:

1. What is the rule?
2. What comes next if I apply it again?

Take 2, 4, 6, 8. The rule is "add 2 each time", so next is 10. Take 🔴🔵🔴🔵. The rule is "alternate red and blue", so next is 🔴.

If you can state the rule in one sentence, you understand the pattern. If you can only say "it just looks right", you don't — yet.