diff --git a/src/cgmath/array.rs b/src/cgmath/array.rs
index eeb3684..6357471 100644
--- a/src/cgmath/array.rs
+++ b/src/cgmath/array.rs
@@ -41,6 +41,7 @@ pub trait Array
     }
 
     fn fold(&self, f: &fn(&T, &T) -> T) -> T;
+    fn each_mut(&mut self, f: &fn(i: uint, x: &mut T));
 }
 
 macro_rules! array(
@@ -90,6 +91,11 @@ macro_rules! array(
             fn fold(&self, f: &fn(&$T, &$T) -> $T) -> $T {
                 gen_fold!($_n)
             }
+
+            #[inline]
+            fn each_mut(&mut self, f: &fn(i: uint, x: &mut $T)) {
+                gen_each_mut!($_n)
+            }
         }
     )
 )
@@ -111,6 +117,12 @@ macro_rules! gen_fold(
     (_4) => (f(&f(&f(self.i(0), self.i(1)), self.i(2)), self.i(3)));
 )
 
+macro_rules! gen_each_mut(
+    (_2) => (f(0, self.mut_i(0)); f(1, self.mut_i(1)););
+    (_3) => (f(0, self.mut_i(0)); f(1, self.mut_i(1)); f(2, self.mut_i(2)););
+    (_4) => (f(0, self.mut_i(0)); f(1, self.mut_i(1)); f(2, self.mut_i(2)); f(3, self.mut_i(3)););
+)
+
 macro_rules! approx_eq(
     (impl<$S:ident> $Self:ty) => (
         impl<$S: Clone + ApproxEq<$S>> ApproxEq<$S> for $Self {
diff --git a/src/cgmath/matrix.rs b/src/cgmath/matrix.rs
index d26193e..5f8cebd 100644
--- a/src/cgmath/matrix.rs
+++ b/src/cgmath/matrix.rs
@@ -196,7 +196,7 @@ pub trait Matrix
 
     #[inline]
     fn swap_r(&mut self, a: uint, b: uint) {
-        for c in self.mut_iter() { c.swap(a, b) }
+        self.each_mut(|_, c| c.swap(a, b))
     }
 
     #[inline]
@@ -222,26 +222,26 @@ pub trait Matrix
     //     *self.mut_cr(cb, rb) = tmp;
     // }
 
-    #[inline] fn neg_self(&mut self) { for c in self.mut_iter() { *c = c.neg() } }
+    #[inline] fn neg_self(&mut self) { self.each_mut(|_, x| *x = x.neg()) }
 
     #[inline] fn mul_s(&self, s: S) -> Self { build(|i| self.i(i).mul_s(s.clone())) }
     #[inline] fn div_s(&self, s: S) -> Self { build(|i| self.i(i).div_s(s.clone())) }
     #[inline] fn rem_s(&self, s: S) -> Self { build(|i| self.i(i).rem_s(s.clone())) }
 
-    #[inline] fn mul_self_s(&mut self, s: S) { for c in self.mut_iter() { *c = c.mul_s(s.clone()) } }
-    #[inline] fn div_self_s(&mut self, s: S) { for c in self.mut_iter() { *c = c.div_s(s.clone()) } }
-    #[inline] fn rem_self_s(&mut self, s: S) { for c in self.mut_iter() { *c = c.rem_s(s.clone()) } }
-
-    #[inline] fn mul_v(&self, v: &V) -> V { build(|i| self.r(i).dot(v)) }
-
     #[inline] fn add_m(&self, other: &Self) -> Self { build(|i| self.i(i).add_v(other.i(i))) }
     #[inline] fn sub_m(&self, other: &Self) -> Self { build(|i| self.i(i).sub_v(other.i(i))) }
 
-    #[inline] fn add_self_m(&mut self, other: &Self) { for (a, b) in self.mut_iter().zip(other.iter()) { *a = a.add_v(b) } }
-    #[inline] fn sub_self_m(&mut self, other: &Self) { for (a, b) in self.mut_iter().zip(other.iter()) { *a = a.sub_v(b) } }
+    #[inline] fn mul_v(&self, v: &V) -> V { build(|i| self.r(i).dot(v)) }
 
     fn mul_m(&self, other: &Self) -> Self;
 
+    #[inline] fn mul_self_s(&mut self, s: S) { self.each_mut(|_, c| *c = c.mul_s(s.clone())) }
+    #[inline] fn div_self_s(&mut self, s: S) { self.each_mut(|_, c| *c = c.div_s(s.clone())) }
+    #[inline] fn rem_self_s(&mut self, s: S) { self.each_mut(|_, c| *c = c.rem_s(s.clone())) }
+
+    #[inline] fn add_self_m(&mut self, other: &Self) { self.each_mut(|i, c| *c = c.add_v(other.c(i))) }
+    #[inline] fn sub_self_m(&mut self, other: &Self) { self.each_mut(|i, c| *c = c.sub_v(other.c(i))) }
+
     fn transpose(&self) -> Self;
     fn transpose_self(&mut self);
     fn determinant(&self) -> S;
diff --git a/src/cgmath/point.rs b/src/cgmath/point.rs
index 650f7f0..7de5392 100644
--- a/src/cgmath/point.rs
+++ b/src/cgmath/point.rs
@@ -69,11 +69,11 @@ pub trait Point
     #[inline] fn add_v(&self, other: &V) -> Self { build(|i| self.i(i).add(other.i(i))) }
     #[inline] fn sub_p(&self, other: &Self) -> V { build(|i| self.i(i).sub(other.i(i))) }
 
-    #[inline] fn mul_self_s(&mut self, s: S) { for x in self.mut_iter() { *x = x.mul(&s) } }
-    #[inline] fn div_self_s(&mut self, s: S) { for x in self.mut_iter() { *x = x.div(&s) } }
-    #[inline] fn rem_self_s(&mut self, s: S) { for x in self.mut_iter() { *x = x.rem(&s) } }
+    #[inline] fn mul_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.mul(&s)) }
+    #[inline] fn div_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.div(&s)) }
+    #[inline] fn rem_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.rem(&s)) }
 
-    #[inline] fn add_self_v(&mut self, other: &V) { for (a, b) in self.mut_iter().zip(other.iter()) { *a = a.add(b) } }
+    #[inline] fn add_self_v(&mut self, other: &V) { self.each_mut(|i, x| *x = x.add(other.i(i))) }
 }
 
 array!(impl<S> Point2<S> -> [S, ..2] _2)
diff --git a/src/cgmath/vector.rs b/src/cgmath/vector.rs
index 5769b09..99d5118 100644
--- a/src/cgmath/vector.rs
+++ b/src/cgmath/vector.rs
@@ -115,19 +115,19 @@ pub trait Vector
     #[inline] fn div_v(&self, other: &Self) -> Self { build(|i| self.i(i).div(other.i(i))) }
     #[inline] fn rem_v(&self, other: &Self) -> Self { build(|i| self.i(i).rem(other.i(i))) }
 
-    #[inline] fn neg_self(&mut self);
+    #[inline] fn neg_self(&mut self) { self.each_mut(|_, x| *x = x.neg()) }
 
-    #[inline] fn add_self_s(&mut self, s: S);
-    #[inline] fn sub_self_s(&mut self, s: S);
-    #[inline] fn mul_self_s(&mut self, s: S);
-    #[inline] fn div_self_s(&mut self, s: S);
-    #[inline] fn rem_self_s(&mut self, s: S);
+    #[inline] fn add_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.add(&s)) }
+    #[inline] fn sub_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.sub(&s)) }
+    #[inline] fn mul_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.mul(&s)) }
+    #[inline] fn div_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.div(&s)) }
+    #[inline] fn rem_self_s(&mut self, s: S) { self.each_mut(|_, x| *x = x.rem(&s)) }
 
-    #[inline] fn add_self_v(&mut self, other: &Self);
-    #[inline] fn sub_self_v(&mut self, other: &Self);
-    #[inline] fn mul_self_v(&mut self, other: &Self);
-    #[inline] fn div_self_v(&mut self, other: &Self);
-    #[inline] fn rem_self_v(&mut self, other: &Self);
+    #[inline] fn add_self_v(&mut self, other: &Self) { self.each_mut(|i, x| *x = x.add(other.i(i))) }
+    #[inline] fn sub_self_v(&mut self, other: &Self) { self.each_mut(|i, x| *x = x.sub(other.i(i))) }
+    #[inline] fn mul_self_v(&mut self, other: &Self) { self.each_mut(|i, x| *x = x.mul(other.i(i))) }
+    #[inline] fn div_self_v(&mut self, other: &Self) { self.each_mut(|i, x| *x = x.div(other.i(i))) }
+    #[inline] fn rem_self_v(&mut self, other: &Self) { self.each_mut(|i, x| *x = x.rem(other.i(i))) }
 
     /// The sum of each component of the vector.
     #[inline] fn comp_add(&self) -> S { self.fold(|a, b| a.add(b)) }
@@ -157,21 +157,7 @@ impl<S: Clone + Num + Ord> Neg<Vec4<S>> for Vec4<S> { #[inline] fn neg(&self) ->
 
 macro_rules! vector(
     (impl $Self:ident <$S:ident> $Slice:ty { $x:ident, $($xs:ident),+ }) => (
-        impl<$S: Clone + Num + Ord> Vector<$S, $Slice> for $Self<$S> {
-            #[inline] fn neg_self(&mut self) { self.$x = -self.$x; $(self.$xs = -self.$xs;)+ }
-
-            #[inline] fn add_self_s(&mut self, s: S) { self.$x = self.$x.add(&s); $(self.$xs = self.$x.add(&s);)+ }
-            #[inline] fn sub_self_s(&mut self, s: S) { self.$x = self.$x.sub(&s); $(self.$xs = self.$x.sub(&s);)+ }
-            #[inline] fn mul_self_s(&mut self, s: S) { self.$x = self.$x.mul(&s); $(self.$xs = self.$x.mul(&s);)+ }
-            #[inline] fn div_self_s(&mut self, s: S) { self.$x = self.$x.div(&s); $(self.$xs = self.$x.div(&s);)+ }
-            #[inline] fn rem_self_s(&mut self, s: S) { self.$x = self.$x.rem(&s); $(self.$xs = self.$x.rem(&s);)+ }
-
-            #[inline] fn add_self_v(&mut self, other: &$Self<$S>) { self.$x = self.$x.add(&other.$x); $(self.$xs = self.$xs.add(&other.$xs);)+ }
-            #[inline] fn sub_self_v(&mut self, other: &$Self<$S>) { self.$x = self.$x.sub(&other.$x); $(self.$xs = self.$xs.sub(&other.$xs);)+ }
-            #[inline] fn mul_self_v(&mut self, other: &$Self<$S>) { self.$x = self.$x.mul(&other.$x); $(self.$xs = self.$xs.mul(&other.$xs);)+ }
-            #[inline] fn div_self_v(&mut self, other: &$Self<$S>) { self.$x = self.$x.div(&other.$x); $(self.$xs = self.$xs.div(&other.$xs);)+ }
-            #[inline] fn rem_self_v(&mut self, other: &$Self<$S>) { self.$x = self.$x.rem(&other.$x); $(self.$xs = self.$xs.rem(&other.$xs);)+ }
-        }
+        impl<$S: Clone + Num + Ord> Vector<$S, $Slice> for $Self<$S>;
     )
 )