Errata for "On the Computation Power of DNA Annealing and Ligation" by
Erik Winfree, in AMS DIMACS Series in Discrete Mathematics and
Theoretical Computer Science Volume Twenty Seven: "DNA Based Computers
- Proceedings of a DIMACS Workshop, April 4, 1995", Editors: Richard
J. Lipton and Eric B. Baum.


* The arrows indicating strand polarity for the circular strand in the
  DX of figures 3, 4, 5, and 7b are incorrect.  They should be pointing the
  opposite direction.  

* The rule molecule shown in figure 7d is impossible; the rightmost two 
  strands should have their polarity reversed. Therefore, there must be two
  rule molecules in figure 7d; one will have 3' sticky ends for input, and 
  the other will have 5' sticky ends for input.  Conversely, the strand 
  polarity is incorrect in figure 7e; there should be just one rule molecule.