a)	b)	c)
-------------------------------------------------------------
front-is-clear				T
front-is-blocked       		T		T
left-is-clear			T	T	T			
left-is-blocked
right-is-clear				T	T			
right-is-blocked		T

next-to-a-beeper 			T	T
not-next-to-a-beeper		T
facing-north			T				
not-facing-north			T	T
facing-east				T		
not-facing-east			T		T
facing-south					T	
not-facing-south		T	T
facing-west					
not-facing-west			T	T	T
any-beepers-in-beeperbag	
no-beepers-in-beeperbag		T	T	T