diff --git a/contrib/algebra/infix.factor b/contrib/algebra/infix.factor
index 576eb0ccd4..ef31b358af 100644
--- a/contrib/algebra/infix.factor
+++ b/contrib/algebra/infix.factor
@@ -90,7 +90,7 @@ M: list3 (eval-infix)
     swap-in-infix \ dup swons swap append ;
 
 M: list2 (eval-infix)
-    2unlist swapd (eval-infix) swap arith-1 word-prop unit append ;
+    2unlist swapd (eval-infix) swap arith-1 word-prop add ;
 
 : build-prefix ( num-of-vars -- quote )
     #! What needs to be placed in front of the eval-infix quote
diff --git a/contrib/cont-responder/todo.factor b/contrib/cont-responder/todo.factor
index cae2b2f0bf..44507cec33 100644
--- a/contrib/cont-responder/todo.factor
+++ b/contrib/cont-responder/todo.factor
@@ -56,7 +56,7 @@ USE: http
 : add-todo-item ( <todo> <item> -- )
   #! Add the item to the todo list
   swap [
-    "items" get swap unit append "items" set
+    "items" get swap add "items" set
   ] bind ;
 
 : >yes/no ( bool -- str )
diff --git a/library/collections/sequences-epilogue.factor b/library/collections/sequences-epilogue.factor
index 1a9f9bb7eb..8f38f28b02 100644
--- a/library/collections/sequences-epilogue.factor
+++ b/library/collections/sequences-epilogue.factor
@@ -96,9 +96,13 @@ M: object contains? ( obj seq -- ? )
     [ over push ] each drop ;
 
 : append ( s1 s2 -- s1+s2 )
-    #! Return a new sequence of the same type as s1.
+    #! Outputs a new sequence of the same type as s1.
     swap [ swap nappend ] immutable ;
 
+: add ( seq elt -- seq )
+    #! Outputs a new sequence of the same type as seq.
+    unit append ;
+
 : append3 ( s1 s2 s3 -- s1+s2+s3 )
     #! Return a new sequence of the same type as s1.
     rot [ [ rot nappend ] keep swap nappend ] immutable ;
diff --git a/library/io/lines.factor b/library/io/lines.factor
index 5e2cb50bb0..76815ddb06 100644
--- a/library/io/lines.factor
+++ b/library/io/lines.factor
@@ -30,9 +30,11 @@ M: line-reader stream-readln ( line -- string )
 
 M: line-reader stream-read ( count line -- string )
     [ delegate stream-read ] keep dup cr> [
-        over empty?
-        [ drop ]
-        [ >r 1 swap tail r> stream-read1 [ append ] when* ] ifte
+        over empty? [
+            drop
+        ] [
+            >r 1 swap tail r> stream-read1 [ add ] when*
+        ] ifte
     ] [
         drop
     ] ifte ;
diff --git a/library/io/stdio.factor b/library/io/stdio.factor
index 6da5211109..2562c8f0a6 100644
--- a/library/io/stdio.factor
+++ b/library/io/stdio.factor
@@ -29,8 +29,3 @@ USING: errors kernel lists namespaces generic strings ;
         swap stdio set
         [ [ close rethrow ] when* ] catch
     ] with-scope ;
-
-TUPLE: stdio-stream ;
-C: stdio-stream ( stream -- stream ) [ set-delegate ] keep ;
-M: stdio-stream stream-auto-flush ( -- ) delegate stream-flush ;
-M: stdio-stream stream-close ( -- ) drop ;
diff --git a/library/ui/events.factor b/library/ui/events.factor
index 5447b17e84..9065935226 100644
--- a/library/ui/events.factor
+++ b/library/ui/events.factor
@@ -19,7 +19,7 @@ M: resize-event handle-event ( event -- )
     world get relayout ;
 
 : button-gesture ( button gesture -- )
-    swap unit append hand hand-clicked handle-gesture drop ;
+    swap add hand hand-clicked handle-gesture drop ;
 
 M: button-down-event handle-event ( event -- )
     button-event-button dup hand button/
diff --git a/library/ui/hand.factor b/library/ui/hand.factor
index c50599f716..957e8b5900 100644
--- a/library/ui/hand.factor
+++ b/library/ui/hand.factor
@@ -78,7 +78,7 @@ C: hand ( world -- hand )
 
 : motion-gesture ( hand gadget gesture -- )
     #! Send a gesture like [ drag 2 ].
-    rot hand-buttons car unit append swap handle-gesture drop ;
+    rot hand-buttons car add swap handle-gesture drop ;
 
 : fire-motion ( hand -- )
     #! Fire a motion gesture to the gadget underneath the hand,
diff --git a/library/ui/hierarchy.factor b/library/ui/hierarchy.factor
index 457b5e5309..fb5fd4e5fb 100644
--- a/library/ui/hierarchy.factor
+++ b/library/ui/hierarchy.factor
@@ -11,7 +11,7 @@ sequences ;
 
 : (add-gadget) ( gadget box -- )
     #! This is inefficient.
-    [ gadget-children swap unit append ] keep
+    [ gadget-children swap add ] keep
     set-gadget-children ;
 
 : unparent ( gadget -- )