Lsystem example

LSystem.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class LSystem : MonoBehaviour
{
    private string axiom = "AA";
    private string rule1 = "B";  //  A -> B
    private string rule2 = "AB"; // B -> AB
    private int index; //   character index
    private string newGen; //new generation

    public void Start()
    {
        Iterate(4); // run 4 iterations
    }

    private void Iterate(int genNum)
    {
        while (genNum > 0) // allow number of iterations
        {
            while (axiom.Length > index) // character length must be bigger than index value
            {
                if (axiom[index].ToString() == "A") newGen += rule1; //apply rule 1
                if (axiom[index].ToString() == "B") newGen += rule2; //apply rule 2
                index++; // increase index value
            }
            axiom = newGen; //store the new generation in the axiom string
            newGen = null; //reset new generation string
            index = 0; //reset index value
            genNum--; //decrease the number of available generations
            print(axiom); //output a generation
        }
    }
}