diff --git a/gaart.scm b/gaart.scm
index 708da91..39799a5 100644
--- a/gaart.scm
+++ b/gaart.scm
@@ -54,14 +54,10 @@
 (define* (blank #:optional (w 0) (h 1))
   (gaart w h (λ (okay? blit! rpos cpos) #f)))
 
-;; TODO: use stock char->grapheme
-(define (char->grapheme char)
-  ((make-grapheme-iterator) char))
-
 (define (char ch)
   (define grapheme (char->grapheme ch))
   (unless grapheme
-    (error (format #f "Unable to convert ~s to a valid unicode grapheme" ch)))
+    (scm-error #f "char" "Unable to convert ~s to a valid unicode grapheme" (list ch) (list ch)))
 
   (gaart
    1 1
@@ -75,12 +71,12 @@
    (λ (okay? blit! rpos cpos)
      ;; Go through each grapheme, print it and advance the position
      ;; depending on the width
-     (stream-fold
+     (fold
       (λ (gr c)
         (blit! rpos c gr)
         (+ c (grapheme-width gr)))
       cpos
-      (string->grapheme-stream str))
+      (string->grapheme-list str))
      #f)))
 
 (define (place-at back row-offset col-offset front)
@@ -95,7 +91,7 @@
   (match-let ((($ <gaart> xw xh _) x))
     (unless (and (<= (+ xw cpos) matte-width)
                  (<= (+ xh rpos) matte-height))
-      (error (format #f "matte-at: Original (~ax~a@~a,~a) must fit inside matte (~ax~a)" xw xh cpos rpos matte-width matte-height)))
+      (scm-error #f "matte-at" "Original (~ax~a@~a,~a) must fit inside matte (~ax~a)" (list xw xh cpos rpos matte-width matte-height) (list x)))
     (place-at (blank matte-width matte-height) rpos cpos x)))
 
 (define* (matte matte-width matte-height x #:key (halign 'center) (valign 'center))
@@ -104,7 +100,7 @@
   (match-let ((($ <gaart> xw xh draw-x) x))
     (unless (and (<= xw width)
                  (<= xh height))
-      (error (format #f "matte: Original (~ax~a) must fit inside matte (~ax~a)" xw xh width height)))
+      (scm-error #f "matte" "Original (~ax~a) must fit inside matte (~ax~a)" (list xw xh width height) (list x)))
 
     (matte-at width height
               (match halign
@@ -186,8 +182,7 @@
   (match-let ((($ <gaart> xw xh draw-x) x)
               (($ <gaart> yw yh draw-y) y))
     (unless (= xw yw)
-      ;; TODO: proper error messages with irritants
-      (error (format #f "vappend2: Widths must be equal: ~a vs ~a" xw yw)))
+      (scm-error #f "vappend2" "Widths must be equal: ~a vs ~a" (list xw yw) (list xw yw)))
     (gaart
      xw (+ xh yh)
      (λ (okay? blit! rpos cpos)
@@ -218,7 +213,7 @@
   (match-let ((($ <gaart> xw xh draw-x) x)
               (($ <gaart> yw yh draw-y) y))
     (unless (= xh yh)
-      (error (format #f "happend2: Heights must be equal: ~a vs ~a" xh yh)))
+      (scm-error #f "happend2" "Heights must be equal: ~a vs ~a" (list xh yh) (list xh yh)))
     (gaart
      (+ xw yw) xh
      (λ (okay? blit! rpos cpos)
diff --git a/gaart/draw.scm b/gaart/draw.scm
index 845de19..c906431 100644
--- a/gaart/draw.scm
+++ b/gaart/draw.scm
@@ -14,4 +14,5 @@
                (blit! (λ (rpos cpos grapheme)
                         (buffer-set! buf rpos cpos grapheme))))
     (draw okay? blit! 0 0)
-    (write-buffer buf port)))
+    (write-buffer buf port)
+    buf))