diff --git a/pitfall/pitfall/annotations.rkt b/pitfall/pitfall/annotations.rkt
index fc743d39..90212221 100644
--- a/pitfall/pitfall/annotations.rkt
+++ b/pitfall/pitfall/annotations.rkt
@@ -58,7 +58,7 @@
   (let ([y2 y1]
         [y1 (+ y1 h)]
         [x2 (+ x1 w)])
-    (match-define (list m0 m1 m2 m3 m4 m5) (· this _ctm))
+    (match-define (list m0 m1 m2 m3 m4 m5) (· this @ctm))
     (let* ([x1 (+ (* x1 m0) (* y1 m2) m4)]
            [y1 (+ (* x1 m1) (* y1 m3) m5)]
            [x2 (+ (* x2 m0) (* y2 m2) m4)]
diff --git a/pitfall/pitfall/document.rkt b/pitfall/pitfall/document.rkt
index 6c96e7ba..9031bd24 100644
--- a/pitfall/pitfall/document.rkt
+++ b/pitfall/pitfall/document.rkt
@@ -38,7 +38,7 @@
 
     ;; initialize mixins
     (send this initVector)
-    (inherit-field _ctm)
+    (inherit-field @ctm)
     (send this initFonts)
     (inherit-field @font-families)
     (send this initText)
@@ -70,7 +70,7 @@
       (set! @y (margin-right (get-field margins (page))))
       ;; flip PDF coordinate system so that the origin is in
       ;; the top left rather than the bottom left
-      (set! _ctm default-ctm-value)
+      (set! @ctm default-ctm-value)
       (send this transform 1 0 0 -1 0 (get-field height (page)))
       this)
 
diff --git a/pitfall/pitfall/vector.rkt b/pitfall/pitfall/vector.rkt
index 50378897..cdd4546d 100644
--- a/pitfall/pitfall/vector.rkt
+++ b/pitfall/pitfall/vector.rkt
@@ -11,11 +11,13 @@
   "path.rkt")
 (provide vector-mixin default-ctm-value)
 
+(define default-ctm-value '(1 0 0 1 0 0))
+
 (define (vector-mixin [% mixin-tester%])
   (class %
     (super-new)
-    (field [_ctm default-ctm-value]
-           [_ctmStack null])
+    (field [@ctm default-ctm-value]
+           [@ctm-stack null])
     (as-methods
      initVector
      save
@@ -45,25 +47,24 @@
      scale)))
 
 
-(define default-ctm-value '(1 0 0 1 0 0))
 
 
 (define/contract (initVector this)
   (->m void?)
-  (set-field! _ctm this default-ctm-value)
-  (set-field! _ctmStack this null))
+  (set-field! @ctm this default-ctm-value)
+  (set-field! @ctm-stack this null))
 
 
 (define/contract (save this)
   (->m object?)
-  (push-field! _ctmStack this (· this _ctm))
+  (push-field! @ctm-stack this (· this @ctm))
   (send this addContent "q"))
 
 
 (define/contract (restore this)
   (->m object?)
-  (set-field! _ctm this (if (pair? (· this _ctmStack))
-                            (pop-field! _ctmStack this)
+  (set-field! @ctm this (if (pair? (· this @ctm-stack))
+                            (pop-field! @ctm-stack this)
                             default-ctm-value))
   (send this addContent "Q"))
 
@@ -228,7 +229,7 @@
 (define/contract (transform this scaleX shearY shearX scaleY mdx mdy)
   (number? number? number? number? number? number? . ->m . object?)
   (define new-ctm (list scaleX shearY shearX scaleY mdx mdy))
-  (set-field! _ctm this (combine-transforms (· this _ctm) new-ctm))
+  (set-field! @ctm this (combine-transforms (· this @ctm) new-ctm))
   (send this addContent (make-transform-string new-ctm)))