This program will produce a small cellular autonoma pattern. It starts with a single dot in the middle of the first row and then each generation applies the rule to the 3 dots above it to set the next row. Click the green flag to run and enter the rule number and the size of the pattern (96 fills the screen).
For more information see here: https://mathworld.wolfram.com/CellularAutomaton.html#:~:text=A%20cellular%20automaton%20is%20a,many%20time%20steps%20as%20desired.