Very simple proof of concept on counting and using the fundamental gate known as the AND gate. This is how the circuit works...
Looking at the switches from LEFT to RIGHT, turning them high a consecutive order, increase the count by one. For example...
SW4. SW3. SW2. SW1.
LOW. LOW. LOW. LOW = 0
LOW. LOW. LOW. HIGH = 1
LOW. LOW. HIGH. HIGH = 2
LOW. HIGH. HIGH. HIGH = 3
HIGH. HIGH. HIGH. HIGH = 4
The corresponding number turns that amount of LEDs on. So 1 = 1 LED on, and so on until all 4 LEDs are on.
This circuit is for understanding how to break tasks down to TRUE/FALSE statements via the AND gate. It is intended to demonstrate that complexity always derives from a combination of fundamentals.
