Spiral Matriz

puts "Введите размер стороны квадрата:"

n = STDIN.gets.to_i

arr = [
  [1]
]

2.upto(n) do |counter|
  range_start = arr.flatten.size + 1
  range_end   = range_start + arr.size - 1
  arr_to_zip  = (range_start..range_end).to_a

  if counter.even?
    # right side
    arr = arr.zip(arr_to_zip).map(&:flatten)
  else
    # left side
    arr = arr_to_zip.reverse.zip(arr).map(&:flatten)
  end

  transposed_arr = arr.transpose
  range_start    = range_end + 1
  range_end      = range_start + transposed_arr.size - 1
  arr_to_zip     = (range_start..range_end).to_a

  if counter.even?
    # bottom side
    arr = transposed_arr.zip(arr_to_zip.reverse).map(&:flatten).transpose
  else
    # top side
    arr = arr_to_zip.zip(transposed_arr).map(&:flatten).transpose
  end
end

# pretty print
max_size = (n**2).digits.size

arr.each do |line|
  pp line.map { |number| number.to_s.rjust(max_size, " ") }
end