Reverse a Linked List (should be refactored)

gistfile1.rb

class Node
  attr_accessor :val, :next
  def initialize(val)
    @val = val
    @next = nil
  end
end

class List
  attr_accessor :head

  def initialize
    @head = nil
    self
  end

  def push(val)
    n = Node.new(val)
    n.next = @head
    @head = n
    self
  end

  def to_s
    s = []
    n = @head
    while n
      s << n.val
      n = n.next
    end
    s.join(', ')
  end

  def reverse
    p, n, x = @head, @head.next, @head.next.next
    while x
      n.next = p
      p.next = nil if p == @head
      p, n, x = n, x, x.next
      n.next = p unless x
    end
    @head = n
  end
end

l = List.new.push(0).push(1).push(2).push(3).push(4).push(5)

puts l
puts l.head.val
l.reverse
puts '------'
puts l
puts l.head.val

Also it doesn't take into account freaky cases like size < 3