anchor.diff:  The proposed robotics challenge seeks to motivate advancement of the state of
   the art toward practical realization.  The challenge is organized into three
   problem domains: arbitrary dimensional chains of integrators, roads with Dubins
  -cars, and manipulation tasks on the assembly line.</p>
  +cars, and factory cart clearing.</p>
   
   <h2 id="problems">Problem Domains</h2>
   
   <ol>
     <li><a href="#scalingcintegrators">scaling chains of integrators</a></li>
  -  <li><a href="#dubinstraffic">Dubins traffic</a></li>
  -  <li><a href="#pickandplace">pick-and-place</a></li>
  +  <li><a href="#dubinstraffic">traffic network of Dubins cars</a></li>
  +  <li><a href="#cartclearing">factory cart clearing</a></li>
   </ol>
   
   <div class="psetting" id="scalingcintegrators">
  
positive.code: </p>
  </div>
  
  <div class="psetting" id="pickandplace">
  <h3>pick-and-place</h3>
  <img src="img/pandp_illustration.png" alt="Illustration of a Baxter robot next to an empty table.  The arms are hanging downward and not in motion." />
  <p>
  The <em>pick-and-place</em> domain concerns dexterous manipulation tasks
  motivated by assembly line activities.  The difficulties present in this problem
  domain will include uncertainty in the shape and dynamics of the end-effector,
  as well as objects that are being grasped, and collision-avoidance with moving
  obstacles that come into the workspace.
  </p>
  </div>
  
negative.code: </div>
  
  <div class="psetting" id="dubinstraffic">
  <h3>traffic network of Dubins cars</h3>
  <img src="img/dtraff_illustration.png" alt="Illustration of 6 Kobuki mobile bases moving around the end of a wall." />
  <p>
  The <em>traffic network of Dubins cars</em> domain involves navigation in a small network of
  two-lane roads with vehicles that have Dubins car dynamics.  There is an
  adversary that selects the motion of other cars.  The adversary is subject to
  assumptions such as obeying traffic rules and not parking unfairly at locations
  