title: intersection() in OpenSCAD
body: <p>I have problems with intersection() in OpenSCAD. Here is the code </p>
  
  <pre><code>intersection(){
  rotate_extrude($fn=200) 
      translate([30, 0, 0]) 
  
  circle(r=5);
  translate([0,0,-50]) 
      cube([100,100,100]);
  
  };
  </code></pre>
  
  <p>It looks good<img src="https://i.stack.imgur.com/fRKex.png" alt="enter image description here">
  until you chance the point of view <img src="https://i.stack.imgur.com/GJyVn.png" alt="enter image description here">
  It is not what I expected. How can I fix it?</p>