This code will flag binary numbers up to 15 using the 4 LEDS connected to pins 10-13.
I wrote (vibe coded) this for my niece as she learns how to program an Arduino.
// We are using 4 LEDs connected to pins 10, 11, 12, and 13
// These 4 LEDs will show numbers in binary (from 0 to 15)
// This is an array.
// An array is a list of values stored under one name.