diff --git a/submission_thesis/CH5_Examples/software.tex b/submission_thesis/CH5_Examples/software.tex
index b4b3278..93f1430 100644
--- a/submission_thesis/CH5_Examples/software.tex
+++ b/submission_thesis/CH5_Examples/software.tex
@@ -87,6 +87,15 @@ A precondition, or requirement for a contract software function
 defines the correct ranges of input conditions for the function
 to operate successfully.
 %
+% C Garret said this was unclear so I have added the following two sentences.
+%
+If we consider a software function to be a {\fg} in the FMMD sense,
+we see that it is can be considered to be a collection of functions that it
+calls and variables/inputs that it uses.
+%
+If we consider these functions and inputs to be its components,
+any erroneous behaviour from them can be considered to be a component failure mode.
+%
 For a software function, a violation of a pre-condition is 
 in effect a failure mode of `one of its components'.
 
@@ -96,6 +105,12 @@ in effect a failure mode of `one of its components'.
 A post condition is a definition of correct behaviour by a function.
 A violated post condition is a symptom of failure, or derived failure mode, of a function.
 Post conditions could  be either  actions performed (i.e. the state of hardware changed) or an output value of a function.
+In pure contract programming, a violation of a pre-condition would not cause the function to
+be executed.
+%
+In implementation code, a pre-condition violation should cause
+an error to be generated, and thus a post condition to fail.
+
 
 \paragraph{Mapping contract `invariant' violations to symptoms and failure modes.}
 
@@ -779,11 +794,6 @@ In this project we are using the ADCMUX, TIMER, PWM and the general purpose comp
 We have to therefore consider the general~computing, CLOCK, PROM and RAM failure modes.
 $$fm (micro-controller) =\{ PROM\_FAULT, RAM\_FAULT, CPU\_FAULT, ALU\_FAULT, CLOCK\_STOPPED \}.$$
 
-
-
-
-
-
 \subsection{Temperature Controller Software Elements FMMD}
 
 We must start from the bottom-up with the software, and consider the hardware elements
@@ -793,20 +803,6 @@ Starting at the bottom
 
 
 
-
-
-
-
-
-
-
-
-
-
-
-
-
-
 %\clearpage
 \section{Conclusion: Software/Hardware FMMD Model}