bottomFloor

local length = 61
local width = 61

local function refuel()
    if turtle.getFuelLevel() < 50 then
        local prev = turtle.getSelectedSlot()
        turtle.select(1)
        if not turtle.refuel(4) then
            print('Need more fuel')
            while not turtle.refuel(4) do
                sleep(3)
            end
        end
        turtle.select(prev)
    end
end

local function tryBackwards()
    refuel()
    turtle.back()
end

local function advance()
    if turtle.getSelectedSlot() == 16 then
        print('Need more materials')
        local empty = true
        while empty do
            for n=2, 16 do
                print (n)
                if turtle.getItemCount(n) > 0 then
                    empty = false
                    turtle.select(n)
                    return
                end
            end
            sleep(3)
        end
    else
        turtle.select(turtle.getSelectedSlot() + 1)
    end
end

local function placeBlock()
    for i = 0, 2, 1 do
        if not turtle.place() or turtle.getItemCount() == 0 then
            while turtle.getItemCount() == 0 do
                advance()
            end
        end
    end
end

local function turnAround(i)
    if i%2 == 1 then
        turtle.turnRight()
        tryBackwards()
        placeBlock()
        turtle.turnRight()
    else
        turtle.turnLeft()
        tryBackwards()
        placeBlock()
        turtle.turnLeft()
    end
end
turtle.select(2)
for i = 1, length, 1 do
    for j = 1, width-1, 1 do
        refuel()
        tryBackwards()
        placeBlock()
    end
    turnAround(i)
end