Revisit the Game of Life while Learning about Extension Methods in C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LifeSimulation.Extensions
{
    static class AppStateExtension
    {
        
        #region Extension methods

        public static void Spawn(this AppState appState, bool random)
        {
            if (random)
                appState.CreateRandomLife(10);
            else
                appState.CreateLifeAtCentre();
        }

        public static void SpawnBlob(this AppState appState, int x, int y, int size)
        {
            //Round object
            int mi = appState.World.Space.GetLength(0) - 1;
            int mj = appState.World.Space.GetLength(1) - 1;

            for (int i = x - size; i <= x + size; i++)
                for (int j = y - size; j <= y + size; j++)
                {
                    if (i > 0 && i < mi && j > 0 && j < mj)
                        if (Math.Sqrt((i - x) * (i - x) + (j - y) * (j - y)) <= size)
                            appState.World.Space[i, j] = appState.LifeModel.MaximumAge;
                }
        }

        #endregion


        #region Private methods

        private static void CreateLifeAtCentre(this AppState appState)
        {
            appState.CreateLifeBlossom(
                appState.World.Space.GetLength(0) / 2,
                appState.World.Space.GetLength(1) / 2
            );
        }


        private static void CreateRandomLife(this AppState appState, int num)
        {
            for (int i = 0; i < num; i++)
                appState.CreateRandomLife();
        }

        private static void CreateRandomLife(this AppState appState)
        {
            int i = appState.Rnd.Next(appState.World.Space.GetLength(0));
            int j = appState.Rnd.Next(appState.World.Space.GetLength(1));

            appState.CreateLifeBlossom(i, j);
        }

        private static void CreateLifeBlossom(this AppState appState, int i, int j)
        {
            int max = appState.LifeModel.MaximumAge;
            appState.CreateLife(i, j, 3, max / 3); //Block
            appState.CreateLife(i, j, 4, max / 2); //Vertical line
            appState.CreateLife(i, j, 5, max / 2); //Horizontal line
            appState.CreateLife(i - 4, j - 4, 1, max); //Spot
            appState.CreateLife(i - 4, j + 4, 1, max); //Spot
            appState.CreateLife(i + 4, j + 4, 1, max); //Spot
            appState.CreateLife(i + 4, j - 4, 1, max); //Spot
            appState.CreateLife(i - 5, j - 5, 1, max); //Spot
            appState.CreateLife(i - 5, j + 5, 1, max); //Spot
            appState.CreateLife(i + 5, j + 5, 1, max); //Spot
            appState.CreateLife(i + 5, j - 5, 1, max); //Spot
        }

        private static void CreateLife(this AppState appState, int i, int j, int type, int age)
        {
            int mi = appState.World.Space.GetLength(0) - 1;
            int mj = appState.World.Space.GetLength(1) - 1;

            switch (type)
            {
                case 1: //Spot
                    if (i > 0 && i < mi && j > 0 && j < mj)
                        appState.World.Space[i, j] = age;
                    break;
                case 2: //Star
                    appState.World.Space[i, j] = age;
                    if (i > 0) appState.World.Space[i - 1, j] = age;
                    if (i < mi) appState.World.Space[i + 1, j] = age;
                    if (j > 0) appState.World.Space[i, j - 1] = age;
                    if (j < mj) appState.World.Space[i, j + 1] = age;
                    break;
                case 3: //Block
                    for (int ii = i - 2; ii <= i + 2; ii++)
                        for (int jj = j - 2; jj <= j + 2; jj++)
                            if (ii > 0 && ii < mi && jj > 0 && jj < mj)
                                appState.World.Space[ii, jj] = age;
                    break;
                case 4: //Vertical line
                    for (int jj = j - 4; jj <= j + 4; jj++)
                        if (jj > 0 && jj < mj)
                            appState.World.Space[i, jj] = age;
                    break;
                case 5: //Horizontal line
                    for (int ii = i - 4; ii <= i + 4; ii++)
                        if (ii > 0 && ii < mi)
                            appState.World.Space[ii, j] = age;
                    break;
            }
        }
        
        #endregion

    }
}