Turtle Chunk Marker

print("Type out how many plots you want")
plots = tonumber(read())
side = 1
block = 0

function checkFuel()
    if turtle.getFuelLevel() < 5 then
        turtle.select(1)
        turtle.refuel(1)
    end
end

function blockSelect()
    slot1 = turtle.getItemCount(16)
    slot2 = turtle.getItemCount(15)
    slot3 = turtle.getItemCount(14)
    slot4 = turtle.getItemCount(13)

    if slot1 > 2 then
        turtle.select(16)
    end

    if slot1 < 2 and slot2 > 2 then
        turtle.select(15)
    end

    if slot2 < 2 and slot3 > 2 then
        turtle.select(14)
    end

    if slot3 < 2 and slot4 > 2 then
        turtle.select(13)
    end
end

function blockPlace()
    checkFuel()
    blockSelect()
    sleep(1)
    turtle.dig()
    turtle.forward()
    turtle.digDown()
    turtle.placeDown()
end

while true do
    if block < 15 and side < 5 then
        blockPlace()
        block = block + 1
    end
    if block == 15 and side < 5 then
        blockPlace()
        turtle.turnRight()
        side = side + 1
        block = 1
    end
    if side == 5 and block < 17 and plots > 1 then
        turtle.turnLeft()
        turtle.forward()
        block = block + 1
        plots = plots - 1
    end
    if side == 5 and block == 17 then
        turtle.turnRight()
        side = 1
        block = 1
    end
end