diff --git a/Makefile b/Makefile
index 9671953..5555260 100644
--- a/Makefile
+++ b/Makefile
@@ -22,7 +22,7 @@ SRC_CRATE      = $(TARGET).rs
 EXTERN_DIR     = $(ROOT_DIR)/extern
 BUILD_DIR      = $(ROOT_DIR)/lib
 
-CFG            = --cfg=color --cfg=geom --cfg=noise --cfg=world
+CFG            = --cfg=color --cfg=geom --cfg=noise --cfg=transform
 
 TEST           = $(TARGET)
 TEST_BUILD_DIR = $(ROOT_DIR)/test
diff --git a/src/color/channel.rs b/src/color/channel.rs
index c879795..dd64fdc 100644
--- a/src/color/channel.rs
+++ b/src/color/channel.rs
@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! Color channel conversions and utility methods
+
 pub trait Channel: Primitive + Orderable {
     priv fn from<T:Channel>(chan: T) -> Self;
     pub fn to_channel<T:Channel>(&self) -> T;
diff --git a/src/color/color.rs b/src/color/color.rs
index 2c3890f..09e6c57 100644
--- a/src/color/color.rs
+++ b/src/color/color.rs
@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! Color types, functions and conversions
+
 pub use self::channel::{Channel, FloatChannel};
 pub use self::hsv::{HSV, ToHSV, HSVA, ToHSVA};
 pub use self::rgb::{RGB, ToRGB, RGBA, ToRGBA};
diff --git a/src/core/core.rs b/src/core/core.rs
index b5d8d1e..f98c178 100644
--- a/src/core/core.rs
+++ b/src/core/core.rs
@@ -13,6 +13,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+// Core datatypes and conversion traits for 3D mathematics
+
 pub use self::dim::Dimensional;
 pub use self::mat::{Mat2, ToMat2, Mat3, ToMat3, Mat4, ToMat4};
 pub use self::quat::{Quat, ToQuat};
diff --git a/src/world/frustum.rs b/src/geom/frustum.rs
similarity index 100%
rename from src/world/frustum.rs
rename to src/geom/frustum.rs
diff --git a/src/geom/geom.rs b/src/geom/geom.rs
index 9e32c17..80dc00e 100644
--- a/src/geom/geom.rs
+++ b/src/geom/geom.rs
@@ -13,6 +13,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! Types and traits for geometric intersections and transformations
+
+pub use self::frustum::{Frustum, FrustumPoints};
 pub use self::plane::Plane3;
 pub use self::point::{Point, Point2, Point3};
 pub use self::ray::Ray3;
@@ -21,5 +24,7 @@ pub mod plane;
 pub mod point;
 pub mod ray;
 
+pub mod frustum;
+
 pub mod octree;
 pub mod quadtree;
diff --git a/src/geom/quadtree.rs b/src/geom/quadtree.rs
index 31a0028..cc94c55 100644
--- a/src/geom/quadtree.rs
+++ b/src/geom/quadtree.rs
@@ -16,3 +16,4 @@
 // TODO
 
 // http://gameprogrammingpatterns.com/spatial-partition.html
+// http://github.com/mozilla/servo/blob/master/src/components/main/compositing/quadtree.rs
diff --git a/src/lmath.rs b/src/lmath.rs
index 8327d7d..ed95591 100644
--- a/src/lmath.rs
+++ b/src/lmath.rs
@@ -26,6 +26,10 @@
 #[path = "core/core.rs"]
 pub mod core;
 
+#[cfg(color)]
+#[path = "color/color.rs"]
+pub mod color;
+
 #[cfg(geom)]
 #[path = "geom/geom.rs"]
 pub mod geom;
@@ -34,10 +38,6 @@ pub mod geom;
 #[path = "noise/noise.rs"]
 pub mod noise;
 
-#[cfg(world)]
-#[path = "world/world.rs"]
-pub mod world;
-
-#[cfg(color)]
-#[path = "color/color.rs"]
-pub mod color;
+#[cfg(transform)]
+#[path = "transform/transform.rs"]
+pub mod transform;
diff --git a/src/noise/noise.rs b/src/noise/noise.rs
index 4defb06..1fb9c35 100644
--- a/src/noise/noise.rs
+++ b/src/noise/noise.rs
@@ -13,5 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+//! Procedural noise generation utility types
+
 pub mod perlin;
 pub mod simplex;
diff --git a/src/world/projection.rs b/src/transform/projection.rs
similarity index 99%
rename from src/world/projection.rs
rename to src/transform/projection.rs
index effd90a..fb5b619 100644
--- a/src/world/projection.rs
+++ b/src/transform/projection.rs
@@ -14,8 +14,7 @@
 // limitations under the License.
 
 use core::Mat4;
-use geom::Plane3;
-use world::Frustum;
+use geom::{Plane3, Frustum};
 
 #[path = "../num_macros.rs"]
 mod num_macros;
diff --git a/src/world/world.rs b/src/transform/transform.rs
similarity index 80%
rename from src/world/world.rs
rename to src/transform/transform.rs
index 590ae68..aa3b2a5 100644
--- a/src/world/world.rs
+++ b/src/transform/transform.rs
@@ -13,8 +13,18 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-pub use self::frustum::{Frustum, FrustumPoints};
 pub use self::projection::{Projection, Perspective, PerspectiveFOV, Ortho};
 
-pub mod frustum;
+use core::{Vec3, Quat};
+
 pub mod projection;
+
+pub trait Transform<T> {}
+
+pub struct QuatTransform<T> {
+    scale: T,
+    translation: Vec3<T>,
+    rotation: Quat<T>,
+}
+
+impl<T> Transform<T> for QuatTransform<T> {}