Update 1735-system-nil.markdown

Author: Joe7M

_build/reference/1735-system-nil.markdown

@@ -1,7 +1,21 @@
 # NIL
 
-> NIL
+> a = NIL
 
-NIL is used to mean 'not set' as distinct from having an INT set to 0
+Sets a variable to nil. NIL is used to mean 'not set' as distinct from having a number set to 0.
 
+### Example 1
 
+```
+b = NIL
+print b   ' Output: Nil
+```
+
+### Example 2
+
+```
+b = NIL
+if(b == NIL) then print "b is not set"
+
+' Output: b is not set
+```