Discussion on: Daily Challenge #2 - String Diamond

def diamond(middle)
  return nil if middle < 0 or middle.even?
  d = []
  (1..middle).step(2).each do |i|
    spaces = " " * ((middle - i).to_i/2)    
    d << "#{spaces}#{"*" * i}#{spaces}"
  end  
  d + d[0..-2].reverse  
end

puts diamond(7)