diff --git a/README.md b/README.md
index a53de9b..17ef487 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,9 @@
 # Driven coupled parametric oscillators
 
-Settling a discussion from the pub.
+Settling a discussion from the pub. Yes, you can extract energy from an infinite source of energy. That's allowed.
+
+In [this video](demo.webm) I am modulating the spring constant.
+
+```
+python main.py
+```
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..0577695
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,4 @@
+jedi==0.13.1
+numpy==1.15.2
+parso==0.3.1
+pygame==1.9.4