State	Variable	Variable
Before any calls	$value1 is 10	$value2 is 15
At the beginning of swap1	$a is 10	$b is 15
At the end of swap1	$a is 15	$b is 10
After swap1	$value1 is 10	$value2 is 15
At the beginning of swap2	$a is 10	$b is 15
At the end of swap2	$a is 15	$b is 10
After swap2	$value1 is 15	$value2 is 10