title: Overriding default value of instance var
body: <p>Given class <code>Obj</code>,</p>
  
  <pre><code>class Obj: NSObject {
      var x = "x"
  }
  </code></pre>
  
  <p>and its subclass, <code>Obj1</code>, how do you change the default value of <code>var x</code>?</p>
  
  <p>Simply setting a new value would make the most sense, but it seems to error out...</p>
  
  <pre><code>class Obj1: Obj {
      var x = "y"
  }
  </code></pre>
  
  <blockquote>
    <p>❗️ Cannot override with a stored property 'x'</p>
  </blockquote>