diff --git a/extra/benchmark/raytracer/raytracer.factor b/extra/benchmark/raytracer/raytracer.factor
index de9b80b4ca..4b60576bd1 100755
--- a/extra/benchmark/raytracer/raytracer.factor
+++ b/extra/benchmark/raytracer/raytracer.factor
@@ -2,9 +2,9 @@
 ! http://www.ffconsultancy.com/free/ray_tracer/languages.html
 
 USING: arrays accessors specialized-arrays.double io io.files
-io.files.temp io.encodings.binary kernel math math.functions
-math.vectors math.parser make sequences sequences.private words
-hints ;
+io.files.temp io.encodings.binary kernel math math.constants
+math.functions math.vectors math.parser make sequences
+sequences.private words hints ;
 IN: benchmark.raytracer
 
 ! parameters
@@ -23,7 +23,7 @@ CONSTANT: levels 3
 
 CONSTANT: size 200
 
-CONSTANT: delta 1.4901161193847656E-8
+: delta ( -- n ) epsilon sqrt ; inline
 
 TUPLE: ray { orig double-array read-only } { dir double-array read-only } ;