local FUEL_BOX = 1
local STONE_BOX = 2
local GLOW_STONE_BOX = 3
local FUEL = 5
local STONE = 6
local GLOW_STONE = 7

function addBlockIfRequired()
    if turtle.getItemCount(STONE) == 0 then
        turtle.select(STONE_BOX)
        turtle.placeUp()

        turtle.select(STONE)
        turtle.suckUp(64)

        turtle.select(STONE_BOX)
        turtle.digUp()
    end
end

function addGlowStoneBlockIfRequired()
    if turtle.getItemCount(GLOW_STONE) == 0 then
        turtle.select(GLOW_STONE_BOX)
        turtle.placeUp()

        turtle.select(GLOW_STONE)
        turtle.suckUp(64)

        turtle.select(GLOW_STONE_BOX)
        turtle.digUp()
    end
end

function refuelIfRequired()
    if turtle.getFuelLevel() < 1280 then
        turtle.select(FUEL_BOX)
        turtle.placeUp()

        turtle.select(FUEL)
        turtle.suckUp(64)
        turtle.refuel(64)

        turtle.select(FUEL_BOX)
        turtle.digUp()
    end
end

function place()
    addBlockIfRequired()
    turtle.select(STONE)
    turtle.placeDown()
end

function placeGlowStone()
    addGlowStoneBlockIfRequired()
    turtle.select(GLOW_STONE)
    turtle.placeDown()
end

function moveForward()
    refuelIfRequired()
    turtle.forward()
end

function moveLayerUp()
    turtle.up()
    turtle.turnRight()
    moveForward()
    turtle.turnLeft()
    moveForward()
end

local x = 1

place()

while true do
    moveLayerUp()

    for i=1,4 do
        turtle.turnLeft()
        for y=1,(x * 2) do
            moveForward()

            if (y +           1) % 8 < 3 or
               (y - (x * 2) + 1) % 8 < 3 then
                place()
            end

            if y          % 8 == 4 and
              (y - x * 2) % 8 == 4 then
                placeGlowStone()
            end
        end
    end

    x = x + 1

    if x > 18 then
        break
    end
end