diff --git a/terranostra.lisp b/terranostra.lisp
index d6a1353..a194b61 100644
--- a/terranostra.lisp
+++ b/terranostra.lisp
@@ -11,7 +11,7 @@
 
 (defstruct patch
 	(pos '(0 0)) ;position
-	(alt 0) ;altitude
+	(alt 50) ;altitude
 	(streams-in NIL)
 	(streams-out NIL))
 
@@ -28,6 +28,33 @@
 	(unless (or (< x 0) (< y 0) (> x (length world)) (> y (length world)))
 		(nth x (nth y world))))
 
+(defun dir2patch (herex herey therex therey)
+	"Calculate the direction to a patch"
+	(cond ((> herex therex)
+			  (cond ((> herey therey) 'SE)					 
+				  ((< herey therey) 'NE)
+				  (T 'E)))
+		((< herex therex)
+			(cond ((> herey therey) 'SW)
+				((< herey therey) 'NW)
+				(T 'W)))
+		(T (cond ((> herey therey) 'S)
+			   ((< herey therey) 'N)
+			   (T NIL)))))
+
+(defun patchindir (x y dir &optional (world *world*))
+	"Return the patch in the given direction"
+	(cond ((eq dir 'N) (coord x (1- y) world))
+		((eq dir 'NE) (coord (1+ x) (1- y) world))
+		((eq dir 'E) (coord (1+ x) y world))
+		((eq dir 'SE) (coord (1+ x) (1+ y) world))
+		((eq dir 'S) (coord x (1+ y) world))
+		((eq dir 'SW) (coord (1- x) (1+ y) world))
+		((eq dir 'W) (coord (1- x) y world))
+		((eq dir 'NW) (coord (1- x) (1- y) world))
+		((null dir) (coord x y world))
+		(T (error "~&Invalid direction ~S"))))
+
 (defun save-topography (file-name &optional (world *world*))
 	"Save the world topography as a csv file"
 	(with-open-file (tf file-name :direction :output)
@@ -41,8 +68,34 @@
 
 (defun create-mountains (world &optional (montaneity 2))
 	"Create mountains and hills. Montaneity determines their number and height."
-	)
+	(do ((n 0 (1+ n)) (npeaks (random (* (/ montaneity 100)
+										  (* (length world)
+											  (length (first world)))))))
+		((= n npeaks) world)
+		(setf world (create-peak (random (first world)) (random (length world))
+						(random (* montaneity 100)) world))))
+
+(defun create-peak (x y height world)
+	"Create a mountain peak at the specified location"
+	(let ((base-height (patch-alt (make-patch))))
+		;;TODO
+		))
 
 (defun create-valleys (world &optional (aqueousness 5))
 	"Create valleys through streams. Aqueousness determines their number."
+	(do ((n 0 (1+ n)) (nstreams (random (* (/ aqueousness 100)
+											(* (length world)
+												(length (first world)))))))
+		((= n nstreams) world)
+		(setf world (create-stream (random (first world))
+						(random (length world)) world))))
+
+(defun create-stream (x y world)
+	"Create a stream, starting at x/y"
+	;;TODO
+	(flet ((lowest-neighbour ())))
 	)
+
+
+;; Initialize the random state (which would otherwise not be very random...)
+(setf *random-state* (make-random-state t))