class Foo
  @cvar = "foo"
  def foo
    @cvar
  end

  def foo=(val)
    @cvar = val
  end
end

a = Foo.new
b = Foo.new

puts "This is @cvar for a:" + a.foo
puts "This is @cvar for b:" + b.foo

a.foo = "baz"

puts "This is @cvar for a:" + a.foo
puts "This is @cvar for b:" + b.foo