; person class - a person has a name, a team position, a location in space,  
;  and some amount of knowledge  
  
( defclass person()  
  (  
   ( name :accessor person-name :initarg :name )  
   ( position :accessor person-position :initarg :position )  
   ( location :accessor person-location :initarg :location )  
   ( knowledge :accessor person-knowledge :initarg :knowledge :initform () )  
  )  
)