diff --git a/cli/tek.rs b/cli/tek.rs
index 0f5ce513..06930bf4 100644
--- a/cli/tek.rs
+++ b/cli/tek.rs
@@ -2,7 +2,7 @@ pub use tek::*;
 pub(crate) use clap::{self, Parser, Subcommand};
 /// Application entrypoint.
 pub fn main () -> Usually<()> {
-     TekCli::parse().run()
+    TekCli::parse().run()
 }
 #[test] fn verify_cli () {
     use clap::CommandFactory;
diff --git a/output/src/area.rs b/output/src/area.rs
index 8c669da1..261ba54c 100644
--- a/output/src/area.rs
+++ b/output/src/area.rs
@@ -76,6 +76,13 @@ pub trait Area<N: Coordinate>: From<[N;4]> + Debug + Copy {
     #[inline] fn centered (&self) -> [N;2] {
         [self.x().minus(self.w()/2.into()), self.y().minus(self.h()/2.into())]
     }
+
+    fn iter_x (&self) -> impl Iterator<Item = N> where N: std::iter::Step {
+        self.x()..(self.x()+self.w())
+    }
+    fn iter_y (&self) -> impl Iterator<Item = N> where N: std::iter::Step {
+        self.y()..(self.y()+self.h())
+    }
 }
 
 impl<N: Coordinate> Area<N> for (N, N, N, N) {
diff --git a/output/src/lib.rs b/output/src/lib.rs
index 3b27b6b6..f6353d1e 100644
--- a/output/src/lib.rs
+++ b/output/src/lib.rs
@@ -1,4 +1,5 @@
 //#![feature(lazy_type_alias)]
+#![feature(step_trait)]
 #![feature(type_alias_impl_trait)]
 #![feature(impl_trait_in_assoc_type)]
 mod direction;    pub use self::direction::*;