To add another program to the project: 
	 
 
	  
		- Right-click on the project. 
		
- Select 
		  Add > 
		  New Item. 
		
- Select 
		  Program from the Visual Studio installed templates. 
		
- Change the name to 
		  sub.pli. 
		
- In the program, change 
		  put skip list ('Hello world' ); to 
		  put skip list ('Hello world sub1' );.