diff --git a/math-replay/Makefile b/math-replay/Makefile
index 4457235..dbf8783 100644
--- a/math-replay/Makefile
+++ b/math-replay/Makefile
@@ -19,4 +19,7 @@ clean:
 	rm -vf $(ALL)
 
 
-.PHONY: all clean
+serve:
+	rackup ./config.ru
+
+.PHONY: all clean serve
diff --git a/math-replay/config.ru b/math-replay/config.ru
new file mode 100755
index 0000000..203d1ce
--- /dev/null
+++ b/math-replay/config.ru
@@ -0,0 +1,6 @@
+#!/usr/bin/env rackup
+use Rack::ContentLength
+root = File.expand_path('./algebra', File.dirname(__FILE__))
+app = Rack::Directory.new(root)
+puts "Serving #{root} (see --help for options)"
+run app