Added examples of calling a transaction that takes an unowned paramet…

…er and an explanation of how returns work.

user_guide/source/tutorial/ownership2.rst

@@ -45,11 +45,18 @@ If ``>>`` is not specified for a certain parameter, then the ownership of that p
 
 If a transaction expects an argument that is ``Unowned``, this means that the transaction cannot take ownership. 
 As a result, it is safe to pass an ``Owned`` reference as an argument to a transaction that expects an ``Unowned`` argument. 
-After the transaction returns, the caller still holds ownership.
+After the transaction returns, the caller still holds ownership. For example:
 
-
-For example, ``transaction bar(Money@Unowned m)`` can accept a 
-``Money`` reference with any ownership and the caller maintains whatever ownership it had initially when it called that transaction.
+::
+
+   transaction logMoney(Money@Unowned m) {
+      ...
+   }
+
+   transction callLogMoney(Money@Owned m) {
+      logMoney(m);
+      // OK; m is still an Owned reference.
+   }
 
 
 Transaction receivers (``this``)

user_guide/source/tutorial/ownership4.rst

@@ -81,4 +81,19 @@ If ownership is no longer desired, ``disown`` can be used to relinquish ownershi
            amount = amount + mergeFrom.amount;
            disown mergeFrom; // We absorbed the value of mergeFrom, so the owner doesn't own it anymore.
        }
-   }
+   }
+
+Return
+--------------
+Return statements affect the type of the returned expression according to the declared return type. For example:
+
+::
+
+   asset contract Candy {}
+
+   contract VendingMachine {
+      transaction dispenseCandy() returns Candy@Owned {
+         Candy c = ... // Get an owned reference somehow
+         return c; // Satisfies return type because ownership of c is transferred to the caller
+         // No accidental loss of c here because c is no longer Owned
+      }