diff --git a/Makefile b/Makefile
index 3901323..2ae09e9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,12 +1,14 @@
 all: build assemble
 
+rwildcard=$(foreach d,$(wildcard $(1:=/*)),$(call rwildcard,$d,$2) $(filter $(subst *,%,$2),$d))
+
 .PHONY: build
 build:
 	mkdir -p build
 	javac -Xlint $(shell find src -type f -name '*.java') -d build
 
 assemble:
-	cd build/; jar cvmf ../MANIFEST.MF ../Elevator.jar $(shell cd build/; find -type f -name '*.class')
+	cd build/; jar cvmf ../MANIFEST.MF ../Elevator.jar $(patsubst %,'%',$(shell cd build; find -name '*.class'))
 
 clean:
 	-rm -r build/*