slot = 1
place = false
function placeUp()

    if place then
        if turtle.getItemCount(slot) == 0 then
            slot = slot + 1
        end
        turtle.select(slot)
        turtle.placeUp()
    end
end

function placeBehind()


    if place then
        if turtle.getItemCount(slot) == 0 then
            slot = slot + 1
        end
        turtle.select(slot)
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.place()
        turtle.turnLeft()
        turtle.turnLeft()
    end
end

function goForward ()
    placeUp()
    turtle.dig()
    turtle.forward()
end

function goUp()
    placeBehind()
    turtle.digUp();
    turtle.up();
end

 function goDown()
    placeBehind()
    turtle.digDown();
    turtle.down();
end

function goLeft()
    turtle.turnLeft()
    goForward()
    turtle.turnLeft()
end

function goRight()
    turtle.turnRight()
    goForward()
    turtle.turnRight()
end

local args = { ... }
if #args < 4 then
    print("Parameters: <size> <depth> <place> <forward>")
else

    local fn = tonumber(args[1])
    local down = tonumber(args[2])
    local needToGoLeft = false
    local needToGoDown = false
    if (args[3] == "1") then
        place = true
    end

    if args[4] == "1" then
        local i = 0
        turtle.digDown()
        turtle.down()
        while i < down do
            local l = 0
            while l < fn do
                local f = 1
                while f < fn do
                    goForward()
                    f = f + 1
                end
                l = l + 1
                if (l < fn) then
                    if (needToGoLeft) then
                        goLeft()
                        needToGoLeft = false
                    else
                        goRight()
                        needToGoLeft = true
                    end
                end
            end
            i = i + 1
            if i < down then
                placeUp()
                turtle.digDown()
                turtle.down()
                turtle.turnLeft()
                turtle.turnLeft()
            end
        end
    else
        local i = 0
        while i < down do
            local l = 0
            while l < fn do
                local f = 1
                while f < fn do
                    if needToGoDown then
                        goDown()
                    else
                        goUp()
                    end
                    f = f + 1
                end
                if needToGoDown then
                    needToGoDown = false
                else
                    needToGoDown = true
                end
                placeBehind()
                l = l + 1
                if (l < fn) then
                    if (needToGoLeft) then
                        turtle.turnLeft()
                        turtle.dig()
                        turtle.forward()
                        turtle.turnRight()
                    else
                        turtle.turnRight()
                        turtle.dig()
                        turtle.forward()
                        turtle.turnLeft()
                    end
                end
            end
            i = i + 1
            if (needToGoLeft) then
                needToGoLeft = false
            else
                needToGoLeft = true
            end
            if i < down then
                turtle.dig()
                turtle.forward()
            end
        end
    end
end