A simple tree

three.ex

defmodule Pyramid do
  def print(n) do
    for row <- 1..n do
      print_row(row)
    end
  end

  defp print_row(row) do
    # Concatenate the asterisks instead of multiplying them
    IO.puts(String.duplicate("*", row))
  end
end

Pyramid.print(5)