diff --git a/Makefile b/Makefile
index 6c011f0..9935878 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,10 @@ clean:
 	rm -f *.png *.pdf *.svg
 
 %.png: %.dot
-	dot -Tpng < $< > $@
+	dot -Tpng -Gdpi=300 < $< > $@
+
+%.eps: %.dot
+	dot -Teps < $< > $@
 
 %.jpg: %.dot
 	dot -Tjpg < $< > $@