diff --git a/rtchallenge/src/lib.rs b/rtchallenge/src/lib.rs
index f1a8623..9fb7a67 100644
--- a/rtchallenge/src/lib.rs
+++ b/rtchallenge/src/lib.rs
@@ -10,3 +10,6 @@ pub mod world;
 
 /// Value considered close enough for PartialEq implementations.
 pub const EPSILON: f32 = 0.00001;
+
+const BLACK: tuples::Color = tuples::Color::new(0., 0., 0.);
+const WHITE: tuples::Color = tuples::Color::new(1., 1., 1.);