diff --git a/basis/math/geometry/rect/rect-docs.factor b/basis/math/geometry/rect/rect-docs.factor
index 3e21dfe307..a892940363 100644
--- a/basis/math/geometry/rect/rect-docs.factor
+++ b/basis/math/geometry/rect/rect-docs.factor
@@ -17,11 +17,6 @@ HELP: <rect> ( loc dim -- rect )
 
 { <zero-rect> <rect> <extent-rect> } related-words
 
-HELP: set-rect-dim ( dim rect -- )
-{ $values { "dim" "a pair of integers" } { "rect" rect } }
-{ $description "Modifies the dimensions of a rectangle." }
-{ $side-effects "rect" } ;
-
 HELP: rect-bounds
 { $values { "rect" rect } { "loc" "a pair of integers" } { "dim" "a pair of integers" } }
 { $description "Outputs the location and dimensions of a rectangle." } ;
diff --git a/basis/math/geometry/rect/rect.factor b/basis/math/geometry/rect/rect.factor
index 7f0bb94092..dd634f4a3b 100644
--- a/basis/math/geometry/rect/rect.factor
+++ b/basis/math/geometry/rect/rect.factor
@@ -7,6 +7,9 @@ IN: math.geometry.rect
 
 TUPLE: rect loc dim ;
 
+GENERIC: rect-loc ( obj -- loc )
+GENERIC: rect-dim ( obj -- dim )
+
 : init-rect ( rect -- rect ) { 0 0 } clone >>loc { 0 0 } clone >>dim ;
 
 : <rect> ( loc dim -- rect ) rect boa ;
@@ -17,6 +20,10 @@ M: array rect-loc ;
 
 M: array rect-dim drop { 0 0 } ;
 
+M: rect rect-loc loc>> ;
+
+M: rect rect-dim dim>> ;
+
 : rect-bounds ( rect -- loc dim ) dup rect-loc swap rect-dim ;
 
 : rect-extent ( rect -- loc ext ) rect-bounds over v+ ;