blur.rb

require 'pp'

class Image
  attr_accessor :image
  def initialize(image)
    @image = image
  end

  def output_image
    @image.each do |e|
      puts e.join('')
    end
  end

  def find_ones
    r = []
    @image.each_with_index do |row, y|
      # puts "starting a row #{y}"
      row.each_with_index do |element, x|
        # puts "visiting element #{x}"
        puts "#{element} #{x} #{y}" if element == 1
        r << [x, y] if element == 1
      end
    end
    r
  end

  def replace_1_to_0
    find_ones.each do |x,y|
      @image[y][x] = '*'
    end
  end

end

image = Image.new([
  [0, 0, 0, 0],
  [0, 1, 0, 0],
  [0, 0, 0, 1],
  [0, 0, 0, 0]
])
image.output_image
puts 'find ones'
pp image.find_ones
image.replace_1_to_0
image.output_image