-- 逆ピラミッド

local num = 10


for j=1,num then
  for i = 1,num then
    turtle.up()
    if (num - i)^2 + i^2 - num ^ 2 < 1 then
      turtle.placeDown()
    end
  end
  turtle.forward()
  for i = 1,num then
    turtle.down()
  end

end