anchor.diff:  <p>TODO: add menu to select an object here (for now we hard-code the exponential func)</p>
   <p>TODO: add things to display and control attributes of the selected object</p>
   
  -
  -<h2>FunctionLib: Exponential</h2>
  +<h2>FunctionLib</h2>
  +<h3>Exponential</h3>
   
   <% svg = MySVG.new(600, 150) %>
   
  
positive.code: 
  <% svg.write("temp-cos.svg") %>
  <%= image_tag("temp-cos.svg") %>
  
negative.code: 
  
  
  <h3>Tanh</h3>
  
  <% svg = MySVG.new(600, 150) %>
  
  