diff --git a/decons.lisp b/decons.lisp
index c971dd0..80b4d1a 100644
--- a/decons.lisp
+++ b/decons.lisp
@@ -5,12 +5,10 @@
   (:local-nicknames (:shape :scopes/shape)
                     (:util :scopes/util))
   (:export #:rapply #:rreduce #:radd #:rmul #:rsub #:rdiv
-           #:combine #:default-deviation #:l2-loss
-           #:*trials* #:trial #:try
+           #:default-deviation #:l2-loss #:trial
            #:line
            #:lgx
-           #:*obj*
-           ))
+           #:*obj* #:*trials* #:try))
 
 (in-package :decons)
 
@@ -45,24 +43,15 @@
 (defun rsub (a b) (rapply #'- a b))
 (defun rdiv (a b) (rapply #'/ a b))
 
-;;;; combine
-
-(defun combine (l1 l2)
-  (mapcar (lambda (x) (scons (pop l1) x)) l2))
-
-(defgeneric scons (a b)
-  (:method (a b) (list a b))
-  (:method (a (b list)) (cons a b)))
-
-;;;; loss calculation
+;;;; loss calculation, collect trial data (parameters, resulting loss)
 
 (defun sqr (x) (* x x))
 
 (defun sum (data) (reduce #'+ data))
 
 (defun default-deviation (observed calculated &key (norm #'sqr))
-  (sum (mapcar (lambda (p) (funcall norm (apply #'- p))) 
-               (combine observed calculated))))
+  (sum (mapcar (lambda (a b) (funcall norm (- a b))) 
+               observed calculated)))
 
 (defun l2-loss (target &key (deviation #'default-deviation))
   (lambda (dataset) ; expectant function
@@ -71,8 +60,6 @@
              (calculated (funcall objective theta)))
         (funcall deviation (cadr dataset) calculated)))))
 
-(defvar *trials* nil)
-
 (defclass trial ()
   ((theta :reader theta :initarg :theta)
    (loss :reader loss :initarg :loss)))
@@ -80,9 +67,6 @@
 (defmethod print-object ((tr trial) stream)
   (shape:print-slots tr stream 'theta 'loss))
 
-(defun try (obj theta)
-  (push (make-instance 'trial :theta theta :loss (funcall obj theta)) *trials*))
-
 ;;;; logging (printing) functions for debugging purposes
 
 (defun lgx (op)
@@ -99,3 +83,8 @@
 ;;;; working area
 
 (defvar *obj* nil)
+
+(defvar *trials* nil)
+
+(defun try (obj theta)
+  (push (make-instance 'trial :theta theta :loss (funcall obj theta)) *trials*))