Task: Forest fire
VB: Public Class ForestFire
    Private _forest(,) As ForestState
    Private _isBuilding As Boolean
    Private _bm As Bitmap
    Private _gen As Integer
    Private _sw As Stopwatch

    Private Const _treeStart As Double = 0.5
    Private Const _f As Double = 0.00001
    Private Const _p As Double = 0.001

    Private Const _winWidth As Integer = 300
    Private Const _winHeight As Integer = 300

    Private Enum ForestState
        Empty
        Burning
        Tree
    End Enum

    Private Sub ForestFire_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Me.ClientSize = New Size(_winWidth, _winHeight)
        ReDim _forest(_winWidth, _winHeight)

        Dim rnd As New Random()
        For i As Integer = 0 To _winHeight - 1
            For j As Integer = 0 To _winWidth - 1
                _forest(j, i) = IIf(rnd.NextDouble <= _treeStart, ForestState.Tree, ForestState.Empty)
            Next
        Next

        _sw = New Stopwatch
        _sw.Start()
        DrawForest()
        Timer1.Start()
    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
        If _isBuilding Then Exit Sub

        _isBuilding = True
        GetNextGeneration()

        DrawForest()
        _isBuilding = False
    End Sub

    Private Sub GetNextGeneration()
        Dim forestCache(_winWidth, _winHeight) As ForestState
        Dim rnd As New Random()

        For i As Integer = 0 To _winHeight - 1
            For j As Integer = 0 To _winWidth - 1
                Select Case _forest(j, i)
                    Case ForestState.Tree
                        If forestCache(j, i) <> ForestState.Burning Then
                            forestCache(j, i) = IIf(rnd.NextDouble <= _f, ForestState.Burning, ForestState.Tree)
                        End If

                    Case ForestState.Burning
                        For i2 As Integer = i - 1 To i + 1
                            If i2 = -1 OrElse i2 >= _winHeight Then Continue For
                            For j2 As Integer = j - 1 To j + 1
                                If j2 = -1 OrElse i2 >= _winWidth Then Continue For
                                If _forest(j2, i2) = ForestState.Tree Then forestCache(j2, i2) = ForestState.Burning
                            Next
                        Next
                        forestCache(j, i) = ForestState.Empty

                    Case Else
                        forestCache(j, i) = IIf(rnd.NextDouble <= _p, ForestState.Tree, ForestState.Empty)
                End Select
            Next
        Next

        _forest = forestCache
        _gen += 1
    End Sub

    Private Sub DrawForest()
        Dim bmCache As New Bitmap(_winWidth, _winHeight)

        For i As Integer = 0 To _winHeight - 1
            For j As Integer = 0 To _winWidth - 1
                Select Case _forest(j, i)
                    Case ForestState.Tree
                        bmCache.SetPixel(j, i, Color.Green)

                    Case ForestState.Burning
                        bmCache.SetPixel(j, i, Color.Red)
                End Select
            Next
        Next

        _bm = bmCache
        Me.Refresh()
    End Sub

    Private Sub ForestFire_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        e.Graphics.DrawImage(_bm, 0, 0)

        Me.Text = "Gen " & _gen.ToString() & " @ " & (_gen / (_sw.ElapsedMilliseconds / 1000)).ToString("F02") & " FPS: Forest Fire"
    End Sub
End Class

PHP: <?php

define('WIDTH',      10);
define('HEIGHT',     10);

define('GEN_CNT',    10);
define('PAUSE',  250000);

define('TREE_PROB',  50);
define('GROW_PROB',   5);
define('FIRE_PROB',   1);

define('BARE',      ' ');
define('TREE',      'A');
define('BURN',      '/');


$forest = makeNewForest();

for ($i = 0; $i < GEN_CNT; $i++) {
    displayForest($forest, $i);
    $forest = getNextForest($forest);
}

displayForest($forest, 'done');
exit;


function makeNewForest() {
    return mapForest([
        'func' => function(){
            return isProb(TREE_PROB) ? TREE : BARE;
        }
    ]);
}


function displayForest($forest, $generationNum) {
    system("clear");
    echo PHP_EOL . "Generation: $generationNum" . PHP_EOL;
    mapForest(['forest' => $forest, 'func' => function($f, $x, $y){
            echo $f[$y][$x] . ($x == WIDTH - 1 ? PHP_EOL : '');
        }
    ]);
    echo PHP_EOL;
    usleep(PAUSE);
}


function getNextForest($oldForest) {
    return mapForest(['forest' => $oldForest, 'func' => function($f, $x, $y){
            switch ($f[$y][$x]) {
                case BURN:
                    return BARE;
                case BARE:
                    return isProb(GROW_PROB) ? TREE : BARE;
                case TREE:
                    $caughtFire = isProb(FIRE_PROB);
                    $ablaze = $caughtFire ? true : getNumBurningNeighbors($f, $x, $y) > 0;
                return $ablaze ? BURN : TREE;
            }
        }
    ]);
}


function getNumBurningNeighbors($forest, $x, $y) {
    $burningNeighbors = mapForest([
        'forest' => $forest, 
        'x1' => $x - 1, 'x2' => $x + 2,
        'y1' => $y - 1, 'y2' => $y + 2,
        'default' => 0,
        'func' => function($f, $x, $y){
            return $f[$y][$x] == BURN ? 1 : 0;
        }
    ]);
    
    $numOnFire = 0;
    foreach ($burningNeighbors as $row) {
        $numOnFire += array_sum($row);
    }
    return $numOnFire;
}


function mapForest($params) {
    $p = array_merge([
        'forest' => [], 
        'func' => function(){echo "default\n";},
        'x1' => 0,
        'x2' => WIDTH,
        'y1' => 0,
        'y2' => HEIGHT,
        'default' => BARE
    ], $params);
    
    $newForest = [];
    for ($y = $p['y1']; $y < $p['y2']; $y++) {
        $newRow = [];
        for ($x = $p['x1']; $x < $p['x2']; $x++) {
            $inBounds = ($x >= 0 && $x < WIDTH && $y >= 0 && $y < HEIGHT);
            $newRow[] = ($inBounds ? $p['func']($p['forest'], $x, $y) : $p['default']);
        }
        $newForest[] = $newRow;
    }
    return $newForest;
}


function isProb($prob) {
    return rand(0, 100) < $prob;
}