Task: Maze generation
Go: package main

import (
    "bytes"
    "fmt"
    "math/rand"
    "time"
)   
    
type maze struct { 
    c  []byte   
    h  []byte   
    v  []byte   
    c2 [][]byte 
    h2 [][]byte 
    v2 [][]byte 
}

func newMaze(rows, cols int) *maze {
    c := make([]byte, rows*cols)              
    h := bytes.Repeat([]byte{'-'}, rows*cols) 
    v := bytes.Repeat([]byte{'|'}, rows*cols) 
    c2 := make([][]byte, rows)                
    h2 := make([][]byte, rows)                
    v2 := make([][]byte, rows)                
    for i := range h2 {
        c2[i] = c[i*cols : (i+1)*cols]
        h2[i] = h[i*cols : (i+1)*cols]
        v2[i] = v[i*cols : (i+1)*cols]
    }
    return &maze{c, h, v, c2, h2, v2}
}

func (m *maze) String() string {
    hWall := []byte("+---")
    hOpen := []byte("+   ")
    vWall := []byte("|   ")
    vOpen := []byte("    ")
    rightCorner := []byte("+\n") 
    rightWall := []byte("|\n")
    var b []byte
    
    for r, hw := range m.h2 {
        
        for _, h := range hw { 
            if h == '-' || r == 0 {
                b = append(b, hWall...)
            } else {
                b = append(b, hOpen...)
            }
        }
        b = append(b, rightCorner...)
        
        for c, vw := range m.v2[r] {
            if vw == '|' || c == 0 {
                b = append(b, vWall...)
            } else {
                b = append(b, vOpen...)
            }
            
            if m.c2[r][c] != 0 {
                b[len(b)-2] = m.c2[r][c]
            }
        }
        b = append(b, rightWall...)
    }
    
    for _ = range m.h2[0] {
        b = append(b, hWall...)
    }
    b = append(b, rightCorner...)
    return string(b)
}

func (m *maze) gen() {
    m.g2(rand.Intn(len(m.c2)), rand.Intn(len(m.c2[0])))
}

const (
    up = iota
    dn
    rt
    lf
)

func (m *maze) g2(r, c int) {
    m.c2[r][c] = ' '
    for _, dir := range rand.Perm(4) {
        switch dir {
        case up:
            if r > 0 && m.c2[r-1][c] == 0 {
                m.h2[r][c] = 0
                m.g2(r-1, c)
            }
        case lf:
            if c > 0 && m.c2[r][c-1] == 0 {
                m.v2[r][c] = 0
                m.g2(r, c-1)
            }
        case dn:
            if r < len(m.c2)-1 && m.c2[r+1][c] == 0 {
                m.h2[r+1][c] = 0
                m.g2(r+1, c)
            }
        case rt:
            if c < len(m.c2[0])-1 && m.c2[r][c+1] == 0 {
                m.v2[r][c+1] = 0
                m.g2(r, c+1)
            }
        }
    }
}

func main() {
    rand.Seed(time.Now().UnixNano())
    m := newMaze(4, 6)
    m.gen()
    fmt.Print(m)
}

PHP: <?php
class Maze 
{
    protected $width;
    protected $height;
    protected $grid;
    protected $path;
    protected $horWalls;
    protected $vertWalls;
    protected $dirs;
    protected $isDebug;

    public function __construct($x, $y, $debug = false)
    {
        $this->width = $x;
        $this->height = $y;
        $this->path = [];        
        $this->dirs = [ [0, -1], [0, 1], [-1, 0], [1, 0]]; // array of coordinates of N,S,W,E
        $this->horWalls = []; // list of removed horizontal walls (---+)        
        $this->vertWalls = [];// list of removed vertical walls (|)        
        $this->isDebug = $debug; // debug flag

        $this->generate();
    }

    protected function generate()
    {        
        $this->initMaze(); // init the stack and an unvisited grid

        $this->walk(mt_rand(0, $this->width-1), mt_rand(0, $this->height-1));
    }

    
    public function printOut()
    {
        $this->log("Horizontal walls: %s", json_encode($this->horWalls));
        $this->log("Vertical walls: %s", json_encode($this->vertWalls));        
        
        $northDoor = mt_rand(0,$this->width-1);
        $eastDoor = mt_rand(0, $this->height-1);

        $str = '+';
        for ($i=0;$i<$this->width;$i++) {
            $str .= ($northDoor == $i) ? '   +' : '---+';
        }
        $str .= PHP_EOL;
        for ($i=0; $i<$this->height; $i++) {
            
            for ($j=0; $j<$this->width; $j++) {
                $str .= (!empty($this->vertWalls[$j][$i]) ? $this->vertWalls[$j][$i] : '|   ');
            }
            $str .= ($i == $eastDoor ? '  ' : '|').PHP_EOL.'+';
            for ($j=0; $j<$this->width; $j++) {
                $str .= (!empty($this->horWalls[$j][$i]) ? $this->horWalls[$j][$i] : '---+');
            }
            $str .= PHP_EOL;
        }
        echo $str;
    }

    
    protected function log(...$params)
    {
        if ($this->isDebug) {
            echo vsprintf(array_shift($params), $params).PHP_EOL;
        }
    }

    private function walk($x, $y)
    {
        $this->log('Entering cell %d,%d', $x, $y);

        $this->grid[$x][$y] = true; 

        $this->path[] = [$x, $y];

        $neighbors = $this->getNeighbors($x, $y);       
        $this->log("Valid neighbors: %s", json_encode($neighbors));

        if(empty($neighbors)) {

            $this->log("Start backtracking along path: %s", json_encode($this->path));
            array_pop($this->path);
            if (!empty($this->path)) {
                $next = array_pop($this->path);
                return $this->walk($next[0], $next[1]);
            }
        } else {            

            shuffle($neighbors);

            foreach ($neighbors as $n) {
                $nextX = $n[0];
                $nextY = $n[1];
                if ($nextX == $x) {
                    $wallY = max($nextY, $y);
                    $this->log("New cell is on the same column (%d,%d), removing %d, (%d-1) horizontal wall", $nextX, $nextY, $x, $wallY);
                    $this->horWalls[$x][min($nextY, $y)] = "   +";
                }
                if ($nextY == $y) {
                    $wallX = max($nextX, $x);
                    $this->log("New cell is on the same row (%d,%d), removing %d,%d vertical wall", $nextX, $nextY, $wallX, $y);
                    $this->vertWalls[$wallX][$y] = "    ";              
                }
                return $this->walk($nextX, $nextY);
            }
        }
    }
    
    
    private function initMaze()
    {
        for ($i=0;$i<$this->width;$i++) {
            for ($j = 0;$j<$this->height;$j++) {
                $this->grid[$i][$j] = false;
            }
        }
    }

    
    private function getNeighbors($x, $y) 
    {       
        $neighbors = [];
        foreach ($this->dirs as $dir) {
            $nextX = $dir[0] + $x;
            $nextY = $dir[1] + $y;
            if (($nextX >= 0 && $nextX < $this->width && $nextY >= 0 && $nextY < $this->height) && !$this->grid[$nextX][$nextY]) {
                $neighbors[] = [$nextX, $nextY];
            }
        }
        return $neighbors;
    }
}

$maze = new Maze(10,10);
$maze->printOut();