I was trying to write a simple array flatten method, but it does not work using instance variable. It works only using class variables. Can anyone tell me why? and how to make it work using instance variables.

class Array @y = [] def flatten_array self.each do |x| if x.class.to_s != 'Array' @y << x else x.flatten_array end end return @y
end
end

a = [1,2,3,4,5] b = [6,7,8] c = [9,10] a1 = [12,13,a,b,c] puts a1.inspect b1 = a1.flatten_array puts b1.inspect