diff --git a/output/src/lib.rs b/output/src/lib.rs
index 7eafda7..3abccd4 100644
--- a/output/src/lib.rs
+++ b/output/src/lib.rs
@@ -1,18 +1,10 @@
 #![feature(step_trait)]
 #![feature(type_alias_impl_trait)]
 #![feature(impl_trait_in_assoc_type)]
-mod direction;    pub use self::direction::*;
-mod coordinate;   pub use self::coordinate::*;
-mod size;         pub use self::size::*;
-mod area;         pub use self::area::*;
-mod output;       pub use self::output::*;
-mod measure;      pub use self::measure::*;
-mod thunk;        pub use self::thunk::*;
-mod op_cond;      pub use self::op_cond::*;
-mod op_iter;      pub use self::op_iter::*;
-mod op_align;     pub use self::op_align::*;
-mod op_bsp;       pub use self::op_bsp::*;
-mod op_transform; pub use self::op_transform::*;
+
+mod space;   pub use self::space::*;
+mod ops;     pub use self::ops::*;
+mod output;  pub use self::output::*;
 
 pub(crate) use std::marker::PhantomData;
 pub(crate) use std::error::Error;
diff --git a/output/src/ops.rs b/output/src/ops.rs
new file mode 100644
index 0000000..b1a5786
--- /dev/null
+++ b/output/src/ops.rs
@@ -0,0 +1,11 @@
+mod align;     pub use self::align::*;
+mod bsp;       pub use self::bsp::*;
+mod cond;      pub use self::cond::*;
+mod map;       pub use self::map::*;
+//mod reduce;    pub use self::reduce::*;
+mod thunk;     pub use self::thunk::*;
+mod transform; pub use self::transform::*;
+
+#[cfg(test)] #[test] fn test_ops () -> Usually<()> {
+    Ok(())
+}
diff --git a/output/src/op_align.rs b/output/src/ops/align.rs
similarity index 100%
rename from output/src/op_align.rs
rename to output/src/ops/align.rs
diff --git a/output/src/op_bsp.rs b/output/src/ops/bsp.rs
similarity index 100%
rename from output/src/op_bsp.rs
rename to output/src/ops/bsp.rs
diff --git a/output/src/collection.rs b/output/src/ops/collect.rs
similarity index 100%
rename from output/src/collection.rs
rename to output/src/ops/collect.rs
diff --git a/output/src/op_cond.rs b/output/src/ops/cond.rs
similarity index 100%
rename from output/src/op_cond.rs
rename to output/src/ops/cond.rs
diff --git a/output/src/op_iter.rs b/output/src/ops/map.rs
similarity index 100%
rename from output/src/op_iter.rs
rename to output/src/ops/map.rs
diff --git a/output/src/op_reduce.rs b/output/src/ops/reduce.rs
similarity index 100%
rename from output/src/op_reduce.rs
rename to output/src/ops/reduce.rs
diff --git a/output/src/thunk.rs b/output/src/ops/thunk.rs
similarity index 100%
rename from output/src/thunk.rs
rename to output/src/ops/thunk.rs
diff --git a/output/src/op_transform.rs b/output/src/ops/transform.rs
similarity index 100%
rename from output/src/op_transform.rs
rename to output/src/ops/transform.rs
diff --git a/output/src/space.rs b/output/src/space.rs
new file mode 100644
index 0000000..8edcb63
--- /dev/null
+++ b/output/src/space.rs
@@ -0,0 +1,10 @@
+mod area;       pub use self::area::*;
+mod coordinate; pub use self::coordinate::*;
+mod direction;  pub use self::direction::*;
+mod measure;    pub use self::measure::*;
+mod size;       pub use self::size::*;
+
+#[cfg(test)] #[test] fn test_space () {
+    use crate::*;
+    assert_eq!(Area::center(&[10u16, 10, 20, 20]), [20, 20]);
+}
diff --git a/output/src/area.rs b/output/src/space/area.rs
similarity index 100%
rename from output/src/area.rs
rename to output/src/space/area.rs
diff --git a/output/src/coordinate.rs b/output/src/space/coordinate.rs
similarity index 100%
rename from output/src/coordinate.rs
rename to output/src/space/coordinate.rs
diff --git a/output/src/direction.rs b/output/src/space/direction.rs
similarity index 100%
rename from output/src/direction.rs
rename to output/src/space/direction.rs
diff --git a/output/src/measure.rs b/output/src/space/measure.rs
similarity index 100%
rename from output/src/measure.rs
rename to output/src/space/measure.rs
diff --git a/output/src/size.rs b/output/src/space/size.rs
similarity index 100%
rename from output/src/size.rs
rename to output/src/space/size.rs
diff --git a/output/src/view.rs b/output/src/view.rs
index cfc0507..f0c88f9 100644
--- a/output/src/view.rs
+++ b/output/src/view.rs
@@ -25,7 +25,10 @@ use crate::*;
 // An ephemeral wrapper around view state and view description,
 // that is meant to be constructed and returned from [Content::content].
 #[cfg(feature = "dsl")]
-pub struct View<'a, T>(pub &'a T, pub SourceIter<'a>);
+pub struct View<'a, T>(
+    pub &'a T,
+    pub SourceIter<'a>
+);
 
 #[cfg(feature = "dsl")]
 impl<'a, O: Output + 'a, T: ViewContext<'a, O>> Content<O> for View<'a, T> {