Project Euler 11 in ruby

GRID = [
  %w!08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08!,
  %w!49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00!,
  %w!81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65!,
  %w!52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91!,
  %w!22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80!,
  %w!24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50!,
  %w!32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70!,
  %w!67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21!,
  %w!24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72!,
  %w!21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95!,
  %w!78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92!,
  %w!16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57!,
  %w!86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58!,
  %w!19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40!,
  %w!04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66!,
  %w!88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69!,
  %w!04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36!,
  %w!20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16!,
  %w!20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54!,
  %w!01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48!
]


class Euler9
  
  
  attr_accessor :result, :guess
  
  def initialize(guess)
    @guess = guess
    @result = 0
    scan_grid
    puts @result
  end

  private

  def scan_grid
    0.upto(19) do |y|
      0.upto(19) do |x|
        scan_x(x, y)
      end
    end
  end

  def scan_x( x, y )
    if GRID[y][x].to_s[0].chr == @guess.to_s
      scan_up( x, y )
      scan_down( x, y )
      scan_left( x, y )
      scan_right( x, y )
      scan_diag_up_left( x, y )
      scan_diag_up_right( x, y )
      scan_diag_down_left( x, y )
      scan_diag_down_right( x, y )
    end
  end
  
  def scan_up(x,y)
    if y >= 3
      product = GRID[y][x].to_i * GRID[y-1][x].to_i * GRID[y-2][x].to_i * GRID[y-3][x].to_i
      if product > @result
        @result = product
      end
    end
  end

  def scan_down(x,y)
    if y <= 16
      product = GRID[y][x].to_i * GRID[y+1][x].to_i * GRID[y+2][x].to_i * GRID[y+3][x].to_i
      if product > @result
        @result = product
      end
    end
  end
  
  def scan_left(x, y)
    if x >= 3
      product = GRID[y][x].to_i * GRID[y][x-1].to_i * GRID[y][x-2].to_i * GRID[y][x-3].to_i
      if product > @result
        @result = product
      end
    end
  end
  
  def scan_right(x, y)
    if x <= 16
      product = GRID[y][x].to_i * GRID[y][x+1].to_i * GRID[y][x+2].to_i * GRID[y][x+3].to_i
      if product > @result
        @result = product
      end
    end
  end
  
  def scan_diag_up_left(x, y)
    if x >= 3 && y >= 3
      product = GRID[y][x].to_i * GRID[y-1][x-1].to_i * GRID[y-2][x-2].to_i * GRID[y-3][x-3].to_i
      if product > @result
        @result = product
      end
    end
  end
  
  def scan_diag_up_right(x, y)
    if x <= 16 && y >= 3
      product = GRID[y][x].to_i * GRID[y-1][x+1].to_i * GRID[y-2][x+2].to_i * GRID[y-3][x+3].to_i
      if product > @result
        @result = product
      end
    end
  end
  
  def scan_diag_down_left( x, y )
    if x >= 3 && y <= 16
      product = GRID[y][x].to_i * GRID[y+1][x-1].to_i * GRID[y+2][x-2].to_i * GRID[y+3][x-3].to_i
      if product > @result
        @result = product
      end
    end
  end

  def scan_diag_down_right( x, y )
    if x <= 16 && y <= 16
      product = GRID[y][x].to_i * GRID[y+1][x+1].to_i * GRID[y+2][x+2].to_i * GRID[y+3][x+3].to_i
      if product > @result
        @result = product
      end
    end
  end

end

Euler9.new(8)