local h = 1
local fuelSlot = 1
local stonePlace = 5
local glassPlace = 9

local blanks = 0

function filler()
 if turtle.getFuelLevel()<10 then
  turtle.select(fuelSlot)
  turtle.refuel(1)
 end
 if turtle.getItemCount(stonePlace)<2 then
  stonePlace = stonePlace + 1
 end

 if turtle.getItemCount(glassPlace )<2 then
  glassPlace = glassPlace + 1
 end

function digMove()
 turtle.down()
 turtle.digDown()
end

function digToBedrock()
 turtle.digDown()
 while not turtle.detectDown() do
  filler()
  digMove()
 end
end

function checkForward()
  turtle.select(glassPlace)
  if (not turtle.detect()) or (turtle.compare()) then
    blanks = blanks + 1
  end
end

function placeWhat()
  blanks = 0
  checkForward()
  turtle.turnLeft()
  checkForward()
  turtle.turnRight()
  turtle.turnRight()
  checkForward()
  turtle.turnLeft()
  if (blanks == 0) then
   turtle.select(stonePlace)
  else
    turtle.select(glassPlace)
  end
end

function movePlace()
 if turtle.up() then
  turtle.placeDown()
  h = h + 1
 else
  turtle.digUp()
 end
end

function run()
  digToBedrock()

  while h < 123 do
   filler()
   if h < 70 then
     placeWhat()
   else
     turtle.select(stonePlace)
   end
   movePlace()
  end
end

run()