ed README

README.md

@@ -459,6 +459,15 @@ recursive definition of the two surreal numbers given.
 ![s2](/test/Data/test_dot_s2.dot.svg) <span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span>
 ![x5](/test/Data/test_dot_x5.dot.svg). 
 
+The thing to note about these tree representations is that they are inefficient,
+the same surreal forms are repeated. The code includes a function `surreal2dag`
+that you use in exactly the same way to generate a DAG (Directed Acyclic Graph)
+representation of the surreal as you see below.
+
+![s2](/test/Data/test_dag_s2.dot.svg) <span>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span>
+![x5](/test/Data/test_dag_x5.dot.svg). 
+
+
 See the code `test/test_dot.jl` for other examples. 
 
 ###  Uniquely surreal functions