anchor.diff:   - So if the particles aren't diffusing, then \( \alpha_2 \neq 0 \)
      * For caged particles, \( \alpha_2 \approx -\frac{1}{5} \)
    - Closely related to caging and cage-breaking behavior
  +   * In a cage, particles move very small distances
  +   * Cage-breaking would involve much larger jumps
  +   * The distribution of "step sizes" would be very non-Gaussian
      
   === What does non-Gaussian mean?
   
  
positive.code: == What does non-Gaussian mean?
  
  === What does non-Gaussian mean?
   - \( \alpha_2 = \frac{\left< x^4 \right> }{3 \left< x^2 \right> } - 1 \)
   - For a Gaussian distribution, \( \left< x^4 \right> = 3\left< x^2 \right> \), so \( \alpha_2 = 0 \) 
  
  === What does non-Gaussian mean?
   - A random walk (diffusion) is Gaussian _at any given time_:
  
negative.code: 
  * Corey O'Hern, Mark Shattuck, Christine Jacobs-Wagner
  * Brad Parry, Ivan Surovtsev, Eric Dufresne, and everyone I talked to
  * Sackler, PEB, and HHMI
  