-- 1 - glass
-- 2 - black
-- 3 - red
Slots = {
    {1, 1, 1, 2, 1, 1, 1},
    {1, 1, 2, 3, 2, 1, 1},
    {1, 2, 3, 3, 3, 2, 1},
    {2, 3, 3, 3, 3, 3, 2},
    {2, 3, 3, 2, 3, 3, 2},
    {1, 2, 2, 1, 2, 2, 1}
}

for line = 1, #Slots do
    for elem = 1, #Slots[line] do
      turtle.select(Slots[line][elem])
      turtle.placeDown()
      turtle.forward()
    end

    for turt = 1, #Slots[line] do
      turtle.back()
    end
    turtle.up()
end