diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)
diff --git a/data.lisp b/data.lisp
index 55a60d7..c89241e 100644
--- a/data.lisp
+++ b/data.lisp
@@ -27,6 +27,10 @@
 						(mapcar #'(lambda (p)
 									  (biome-char (patch-biome p)))
 							row) "")))))
+
+	(defun save-world ()
+		;;TODO
+		)
 	
 	(defun coord (x y)
 		"Return the patch at the given coordinates or NIL if out of bounds"

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)
diff --git a/data.lisp b/data.lisp
index 55a60d7..c89241e 100644
--- a/data.lisp
+++ b/data.lisp
@@ -27,6 +27,10 @@
 						(mapcar #'(lambda (p)
 									  (biome-char (patch-biome p)))
 							row) "")))))
+
+	(defun save-world ()
+		;;TODO
+		)
 	
 	(defun coord (x y)
 		"Return the patch at the given coordinates or NIL if out of bounds"
diff --git a/item-classes.lisp b/item-classes.lisp
index 1286189..2643ca9 100644
--- a/item-classes.lisp
+++ b/item-classes.lisp
@@ -50,7 +50,7 @@
 		(max-weight :reader .max-weight :initarg :max-weight :initform -1)
 		(capacity :reader .capacity :initarg :capacity :initform 0)))
 
-(defclass species (feature)
+(defclass animal (feature)
 	;; An animal species
 	(;; species properties
 		(strength :accessor .strength :initarg :strength :initform 1)
@@ -59,7 +59,7 @@
 		(group-size :reader .group-size :initarg :group-size :initform 1)
 		(habitat :reader .habitat :initarg :habitat :initform '())
 		;; individual properties
-		(id :reader .id :initarg :id :initform -1)
+		(id :reader .id :initarg :id :initform -1))
 	(:default-initargs :destroy-with '(weapon) :movable T))
 
 

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)
diff --git a/data.lisp b/data.lisp
index 55a60d7..c89241e 100644
--- a/data.lisp
+++ b/data.lisp
@@ -27,6 +27,10 @@
 						(mapcar #'(lambda (p)
 									  (biome-char (patch-biome p)))
 							row) "")))))
+
+	(defun save-world ()
+		;;TODO
+		)
 	
 	(defun coord (x y)
 		"Return the patch at the given coordinates or NIL if out of bounds"
diff --git a/item-classes.lisp b/item-classes.lisp
index 1286189..2643ca9 100644
--- a/item-classes.lisp
+++ b/item-classes.lisp
@@ -50,7 +50,7 @@
 		(max-weight :reader .max-weight :initarg :max-weight :initform -1)
 		(capacity :reader .capacity :initarg :capacity :initform 0)))
 
-(defclass species (feature)
+(defclass animal (feature)
 	;; An animal species
 	(;; species properties
 		(strength :accessor .strength :initarg :strength :initform 1)
@@ -59,7 +59,7 @@
 		(group-size :reader .group-size :initarg :group-size :initform 1)
 		(habitat :reader .habitat :initarg :habitat :initform '())
 		;; individual properties
-		(id :reader .id :initarg :id :initform -1)
+		(id :reader .id :initarg :id :initform -1))
 	(:default-initargs :destroy-with '(weapon) :movable T))
 
 
diff --git a/item-methods.lisp b/item-methods.lisp
index 9440b90..3c5e02e 100644
--- a/item-methods.lisp
+++ b/item-methods.lisp
@@ -22,6 +22,9 @@
 				   (leading-vowl (.name d)) (leading-vowel (.name tl)))
 			NIL)))
 
+;;TODO (defmethod attack ((f feature) (tl tool)))
+;;TODO (defmethod attack ((a animal) (w weapon)))
+
 (defmethod update ((a animal))
 	(random-move a))
 	

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)
diff --git a/data.lisp b/data.lisp
index 55a60d7..c89241e 100644
--- a/data.lisp
+++ b/data.lisp
@@ -27,6 +27,10 @@
 						(mapcar #'(lambda (p)
 									  (biome-char (patch-biome p)))
 							row) "")))))
+
+	(defun save-world ()
+		;;TODO
+		)
 	
 	(defun coord (x y)
 		"Return the patch at the given coordinates or NIL if out of bounds"
diff --git a/item-classes.lisp b/item-classes.lisp
index 1286189..2643ca9 100644
--- a/item-classes.lisp
+++ b/item-classes.lisp
@@ -50,7 +50,7 @@
 		(max-weight :reader .max-weight :initarg :max-weight :initform -1)
 		(capacity :reader .capacity :initarg :capacity :initform 0)))
 
-(defclass species (feature)
+(defclass animal (feature)
 	;; An animal species
 	(;; species properties
 		(strength :accessor .strength :initarg :strength :initform 1)
@@ -59,7 +59,7 @@
 		(group-size :reader .group-size :initarg :group-size :initform 1)
 		(habitat :reader .habitat :initarg :habitat :initform '())
 		;; individual properties
-		(id :reader .id :initarg :id :initform -1)
+		(id :reader .id :initarg :id :initform -1))
 	(:default-initargs :destroy-with '(weapon) :movable T))
 
 
diff --git a/item-methods.lisp b/item-methods.lisp
index 9440b90..3c5e02e 100644
--- a/item-methods.lisp
+++ b/item-methods.lisp
@@ -22,6 +22,9 @@
 				   (leading-vowl (.name d)) (leading-vowel (.name tl)))
 			NIL)))
 
+;;TODO (defmethod attack ((f feature) (tl tool)))
+;;TODO (defmethod attack ((a animal) (w weapon)))
+
 (defmethod update ((a animal))
 	(random-move a))
 	
diff --git a/naledi.lisp b/naledi.lisp
index 1f06386..1dae3d9 100644
--- a/naledi.lisp
+++ b/naledi.lisp
@@ -9,12 +9,15 @@
 
 
 (defparameter *debugging* T)
+(defparameter *logfile* "naledi.log")
 
+(ql:quickload :bordeaux-threads)
 (ql:quickload :croatoan)
 (use-package :croatoan)
 
 (load "util.lisp")
-(load "classes.lisp")
+(load "item-classes.lisp")
+(load "item-methods.lisp")
 (load "data.lisp")
 (load "world.lisp")
 (load "items.lisp")
@@ -24,6 +27,7 @@
 (defun start-game ()
 	(setf *random-state* (make-random-state t))
 	(create-world 250)
+	(bt:make-thread #'update-loop :name "world-thread")
 	(with-screen (scr :input-echoing nil :input-blocking t :enable-colors t
 					 :cursor-visibility nil :input-reading :unbuffered)
 		(splash-screen scr)

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)
diff --git a/data.lisp b/data.lisp
index 55a60d7..c89241e 100644
--- a/data.lisp
+++ b/data.lisp
@@ -27,6 +27,10 @@
 						(mapcar #'(lambda (p)
 									  (biome-char (patch-biome p)))
 							row) "")))))
+
+	(defun save-world ()
+		;;TODO
+		)
 	
 	(defun coord (x y)
 		"Return the patch at the given coordinates or NIL if out of bounds"
diff --git a/item-classes.lisp b/item-classes.lisp
index 1286189..2643ca9 100644
--- a/item-classes.lisp
+++ b/item-classes.lisp
@@ -50,7 +50,7 @@
 		(max-weight :reader .max-weight :initarg :max-weight :initform -1)
 		(capacity :reader .capacity :initarg :capacity :initform 0)))
 
-(defclass species (feature)
+(defclass animal (feature)
 	;; An animal species
 	(;; species properties
 		(strength :accessor .strength :initarg :strength :initform 1)
@@ -59,7 +59,7 @@
 		(group-size :reader .group-size :initarg :group-size :initform 1)
 		(habitat :reader .habitat :initarg :habitat :initform '())
 		;; individual properties
-		(id :reader .id :initarg :id :initform -1)
+		(id :reader .id :initarg :id :initform -1))
 	(:default-initargs :destroy-with '(weapon) :movable T))
 
 
diff --git a/item-methods.lisp b/item-methods.lisp
index 9440b90..3c5e02e 100644
--- a/item-methods.lisp
+++ b/item-methods.lisp
@@ -22,6 +22,9 @@
 				   (leading-vowl (.name d)) (leading-vowel (.name tl)))
 			NIL)))
 
+;;TODO (defmethod attack ((f feature) (tl tool)))
+;;TODO (defmethod attack ((a animal) (w weapon)))
+
 (defmethod update ((a animal))
 	(random-move a))
 	
diff --git a/naledi.lisp b/naledi.lisp
index 1f06386..1dae3d9 100644
--- a/naledi.lisp
+++ b/naledi.lisp
@@ -9,12 +9,15 @@
 
 
 (defparameter *debugging* T)
+(defparameter *logfile* "naledi.log")
 
+(ql:quickload :bordeaux-threads)
 (ql:quickload :croatoan)
 (use-package :croatoan)
 
 (load "util.lisp")
-(load "classes.lisp")
+(load "item-classes.lisp")
+(load "item-methods.lisp")
 (load "data.lisp")
 (load "world.lisp")
 (load "items.lisp")
@@ -24,6 +27,7 @@
 (defun start-game ()
 	(setf *random-state* (make-random-state t))
 	(create-world 250)
+	(bt:make-thread #'update-loop :name "world-thread")
 	(with-screen (scr :input-echoing nil :input-blocking t :enable-colors t
 					 :cursor-visibility nil :input-reading :unbuffered)
 		(splash-screen scr)
diff --git a/util.lisp b/util.lisp
index da2029c..02a7e3e 100644
--- a/util.lisp
+++ b/util.lisp
@@ -14,7 +14,9 @@
 	"If *debugging* is true, print str"
 	`(when *debugging* (format t ,str ,@format-args)))
 
-;;TODO write `logging' macro
+(defmacro logging (str &rest format-args)
+	"Write an entry to *logfile*"
+	`(write-to-file (format NIL ,str ,@format-args) *logfile* T))
 
 (defmacro set-list (value &rest var-list)
 	"Set each symbol in var-list to value"

diff --git a/TODO b/TODO
index 4583e01..7b2cf8a 100644
--- a/TODO
+++ b/TODO
@@ -9,6 +9,8 @@
 GAME
 
 * introduce multithreading, update functions
+
+* set up an ASDF system, define packages
 	
 * (I am legion...)
 
diff --git a/animals.lisp b/animals.lisp
index 3e0cabd..a253200 100644
--- a/animals.lisp
+++ b/animals.lisp
@@ -12,56 +12,56 @@
 ;;XXX water species?
 ;;XXX small mammals -> hills
 
-(new-item species impala
+(new-item animal impala
 	:strength 3 :max-health 10
 	:aggression 0 :group-size 15
 	:habitat '(forest grassland)
 	:char #\a :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species warthog
+(new-item animal warthog
 	:strength 5 :max-health 10
 	:aggression 2 :group-size 5
 	:habitat '(forest grassland swamp hill)
 	:char #\p :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species lion
+(new-item animal lion
 	:strength 18 :max-health 25
 	:aggression 20 :group-size 6
 	:habitat '(grassland swamp desert)
 	:char #\C :color :red
 	:drops NIL) ;TODO
 
-(new-item species leopard
+(new-item animal leopard
 	:strength 20 :max-health 30
 	:aggression 20 :group-size 1
 	:habitat '(forest grassland hill)
 	:char #\C :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species cheetah
+(new-item animal cheetah
 	:strength 15 :max-health 20
 	:aggression 10 :group-size 1
 	:habitat '(grassland)
 	:char #\C :color :yellow
 	:drops NIL) ;TODO
 
-(new-item species elephant
+(new-item animal elephant
 	:strength 40 :max-health 50
 	:aggression 5 :group-size 4
 	:habitat '(forest grassland)
 	:char #\E :color :cyan
 	:drops NIL) ;TODO
 
-(new-item species buffalo
+(new-item animal buffalo
 	:strength 15 :max-health 20
 	:aggression 5 :group-size 10
 	:habitat '(swamp grassland)
 	:char #\B :color :magenta
 	:drops NIL) ;TODO
 
-(new-item species oryx
+(new-item animal oryx
 	:strength 8 :max-health 12
 	:aggression 0 :group-size 2
 	:habitat '(desert grassland)
diff --git a/data.lisp b/data.lisp
index 55a60d7..c89241e 100644
--- a/data.lisp
+++ b/data.lisp
@@ -27,6 +27,10 @@
 						(mapcar #'(lambda (p)
 									  (biome-char (patch-biome p)))
 							row) "")))))
+
+	(defun save-world ()
+		;;TODO
+		)
 	
 	(defun coord (x y)
 		"Return the patch at the given coordinates or NIL if out of bounds"
diff --git a/item-classes.lisp b/item-classes.lisp
index 1286189..2643ca9 100644
--- a/item-classes.lisp
+++ b/item-classes.lisp
@@ -50,7 +50,7 @@
 		(max-weight :reader .max-weight :initarg :max-weight :initform -1)
 		(capacity :reader .capacity :initarg :capacity :initform 0)))
 
-(defclass species (feature)
+(defclass animal (feature)
 	;; An animal species
 	(;; species properties
 		(strength :accessor .strength :initarg :strength :initform 1)
@@ -59,7 +59,7 @@
 		(group-size :reader .group-size :initarg :group-size :initform 1)
 		(habitat :reader .habitat :initarg :habitat :initform '())
 		;; individual properties
-		(id :reader .id :initarg :id :initform -1)
+		(id :reader .id :initarg :id :initform -1))
 	(:default-initargs :destroy-with '(weapon) :movable T))
 
 
diff --git a/item-methods.lisp b/item-methods.lisp
index 9440b90..3c5e02e 100644
--- a/item-methods.lisp
+++ b/item-methods.lisp
@@ -22,6 +22,9 @@
 				   (leading-vowl (.name d)) (leading-vowel (.name tl)))
 			NIL)))
 
+;;TODO (defmethod attack ((f feature) (tl tool)))
+;;TODO (defmethod attack ((a animal) (w weapon)))
+
 (defmethod update ((a animal))
 	(random-move a))
 	
diff --git a/naledi.lisp b/naledi.lisp
index 1f06386..1dae3d9 100644
--- a/naledi.lisp
+++ b/naledi.lisp
@@ -9,12 +9,15 @@
 
 
 (defparameter *debugging* T)
+(defparameter *logfile* "naledi.log")
 
+(ql:quickload :bordeaux-threads)
 (ql:quickload :croatoan)
 (use-package :croatoan)
 
 (load "util.lisp")
-(load "classes.lisp")
+(load "item-classes.lisp")
+(load "item-methods.lisp")
 (load "data.lisp")
 (load "world.lisp")
 (load "items.lisp")
@@ -24,6 +27,7 @@
 (defun start-game ()
 	(setf *random-state* (make-random-state t))
 	(create-world 250)
+	(bt:make-thread #'update-loop :name "world-thread")
 	(with-screen (scr :input-echoing nil :input-blocking t :enable-colors t
 					 :cursor-visibility nil :input-reading :unbuffered)
 		(splash-screen scr)
diff --git a/util.lisp b/util.lisp
index da2029c..02a7e3e 100644
--- a/util.lisp
+++ b/util.lisp
@@ -14,7 +14,9 @@
 	"If *debugging* is true, print str"
 	`(when *debugging* (format t ,str ,@format-args)))
 
-;;TODO write `logging' macro
+(defmacro logging (str &rest format-args)
+	"Write an entry to *logfile*"
+	`(write-to-file (format NIL ,str ,@format-args) *logfile* T))
 
 (defmacro set-list (value &rest var-list)
 	"Set each symbol in var-list to value"
diff --git a/world.lisp b/world.lisp
index df9744f..d5f683e 100644
--- a/world.lisp
+++ b/world.lisp
@@ -160,6 +160,27 @@
 	(dotimes (s (round (/ (expt size 2) 2000)))
 		(generate-stream (random size) (random size))))
 
+(let ((uptime 0))
+	(defun update-loop ()
+		"The main loop, updating the world in the background"
+		;;Update all items in each patch
+		(dotimes (y (world-size))
+			(dotimes (x (world-size))
+				(dolist (i (patch-items (coord x y)))
+					(update i))))
+		;;Update all items each player has
+		;;TODO
+		;;Save the world and start over
+		(save-world) ;XXX not yet implemented
+		(incf uptime)
+		(logging "Ran update ~S." uptime)
+		(sleep 0.5)
+		(update-loop)) ;;requires Tail-Call Optimization
+
+	(defun age-of-the-world () uptime)
+
+	(defun reset-world-age () (setf uptime 0)))
+
 (defun describe-patch (p)
 	"Return a list of lines describing this patch."
     (list (string-upcase (biome-name (patch-biome p))) ""