local y = 0
local x = 0
local z = 0
local i = 0
local a = 0
local groesseX = 10
local groesseY = 10
local groesseZ = 30
local richtung = false

function fGRABEN()
  if turtle.detect()==true then
    turtle.dig()
  end
  turtle.forward()
end

function fSEITE()
  if richtung==true then
    turtle.turnRight()
    fGRABEN()
    turtle.turnRight()
    richtung = false
  else
    turtle.turnLeft()
    fGRABEN()
    turtle.turnLeft()
    richtung = true
  end
  y = y + 1
end

fKOHLE()
  if turtle.getFuelLevel()<=y + x + z then
    fBACK()
  else
    if fSTOCK() == true then
      fBACK()
    end
  end
end

function fSTOCK()
  for i=1,16 do
    if turtle.getItemCount(i)==0 then
      a = a + 1
    end
  end
  if a <= 11 then
    return true
  end
end

function fBACK()
  turtle.turnLeft()
  for b=1,y-1 do
    turtle.forward()
  end
  turtle.turnLeft()
  for b=1, 16 do
    turtle.select(b)
    turtle.drop()
  end
  turtle.turnRight()
  turtle.forward()
  turtle.forward()
  turtle.turnLeft()
  turtle.select(1)
  turtle.suck(64)
  turtle.turnRight()
  turtle.turnRight()
  for f=1,y do
    turtle.forward()
  end
end

function fMAIN()
  for j=1, groesseX do
    for i=1,groesseY do
      fGRABEN()
    end
    fSEITE()
    if y == 2 then
       y = 0
       fKOHLE()
    end
    x = x + 1
  end
end