Creating random maze in Go

/*
Create a random maze
*/

package main

import (
    "fmt"
    "math/rand"
    "time"
)

const (
    mazewidth   = 15
    mazeheight  = 15
)

type room struct {
    x, y int
}

func (r room) String() string {
    return fmt.Sprintf("(%d,%d)", r.x, r.y)
}

func (r room) id() int {
    return (r.y * mazewidth) + r.x
}

// whetwher walls are  open or not.
// There are (num_rooms * 2) walls. Some are on borders, but nevermind them ;)
type wallregister [mazewidth * mazeheight * 2]bool

var wr = wallregister{}

// rooms are visited or not
type roomregister [mazewidth * mazeheight]bool

var rr = roomregister{}

func main() {
    rand.Seed(time.Now().Unix())

    stack := make([]room, 0, mazewidth*mazeheight)
    start := room{0, 0}

    // mark start position visited
    rr[start.id()] = true

    // put start position on stack 
    stack = append(stack, room{0, 0})

    for len(stack) > 0 {
        // current node is in top of the stack
        current := stack[len(stack)-1]

        // Slice of neighbors we can move
        availneighbrs := current.nonvisitedneighbors()

        // cannot move. Remove this room from stack and continue
        if len(availneighbrs) < 1 {
            stack = stack[:len(stack)-1]
            continue
        }

        // pick a random room to move.
        next := availneighbrs[rand.Intn(len(availneighbrs))]

        // mark next visited
        rr[next.id()] = true

        // open wall between current and next:
        first, second := orderrooms(current, next)

        // second is either at the right or bottom of first.
        if second.x == first.x+1 {
            wr[first.id()*2] = true
        } else if second.y == first.y+1 {
            wr[first.id()*2+1] = true
        } else { // probably impossible or maybe not...
            panic("Wot?!?")
        }
        // push next to stack
        stack = append(stack, next)
    }

    // print maze

    // print upper border
    for x := 0; x < mazewidth; x++ {
        if x == 0 {
            fmt.Printf("   ")
        } else {
            fmt.Printf("_ ")
        }
    }
    fmt.Println()

    for y := 0; y < mazeheight; y++ {
        fmt.Printf("|") // left border
        for x := 0; x < mazewidth; x++ {

            id := room{x, y}.id()
            right := "|"
            bottom := "_"
            if wr[id*2] {
                right = " "
            }
            if wr[id*2+1] {
                bottom = " "
            }
            if x == mazewidth-1 && y == mazeheight-1 {
                right = " "
            }
            fmt.Printf("%s%s", bottom, right)
        }
        fmt.Println()
    }
}

// return slice of neighbor rooms
func (r room) neighbors() []room {
    rslice := make([]room, 0, 4)
    if r.x < mazewidth-1 {
        rslice = append(rslice, room{r.x + 1, r.y})
    }
    if r.x > 0 {
        rslice = append(rslice, room{r.x - 1, r.y})
    }
    if r.y < mazeheight-1 {
        rslice = append(rslice, room{r.x, r.y + 1})
    }
    if r.y > 0 {
        rslice = append(rslice, room{r.x, r.y - 1})
    }
    return rslice
}

// return rooms that are not visited yet
func (r room) nonvisitedneighbors() []room {
    rslice := make([]room, 0, 4)
    for _, r := range r.neighbors() {
        if rr[r.id()] == false {
            rslice = append(rslice, r)
        }
    }
    return rslice
}

// order to rooms by closeness to origin (upperleft)
func orderrooms(room1, room2 room) (room, room) {
    dist1 := room1.x*room1.x + room1.y*room1.y
    dist2 := room2.x*room2.x + room2.y*room2.y
    if dist1 < dist2 {
        return room1, room2
    }
    return room2, room1
}

http://play.golang.org/p/8W_FbBfUjb (You can run it here. But since time.Now() is fixed there, you will always get same maze.)

In any aspect of it, how does it look?