diff --git a/README.md b/README.md
index c1b968e..a53de9b 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,3 @@
-# patrick_wheels
+# Driven coupled parametric oscillators
 
-Simulating Patrick's wheels
\ No newline at end of file
+Settling a discussion from the pub.
diff --git a/demo.webm b/demo.webm
new file mode 100644
index 0000000..21ea63f
Binary files /dev/null and b/demo.webm differ
diff --git a/main.py b/main.py
index 215a8c7..31a9752 100644
--- a/main.py
+++ b/main.py
@@ -12,6 +12,8 @@ pygame.display.set_caption("Patrick")
 running = True
 clock = pygame.time.Clock()
 
+data = []
+
 
 def physics():
     for ball in balls:
@@ -36,13 +38,22 @@ def boost():
     norm = np.array([vector[1], -vector[0]])
     balls[1].velocity += norm * .5
 
+def modulate():
+    x = pygame.mouse.get_pos()[0] 
+    fraction = x / SIZE[0]
+    springs[-1].k = fraction*3 + 0.05
+    springs[-2].k = fraction*3 + 0.05
+    pygame.draw.rect(screen, (30, 30, 30), (0, 0, x, SIZE[1]))
+
 
 if __name__ == '__main__':
     balls = [Ball(0., 0., fixed=True),
              Ball(0., 100.),
              Ball(20., 120.),
              Ball(-20., 120.),
-             Ball(0., 80.)]
+             Ball(0., 80.),
+             Ball(40., 100.),
+             Ball(-40., 100.)]
     springs = [
         Spring(balls[0], balls[1], length=100, k=3),
         Spring(balls[1], balls[2], k=5),
@@ -50,7 +61,9 @@ if __name__ == '__main__':
         Spring(balls[2], balls[3], k=5),
         Spring(balls[1], balls[4], k=5),
         Spring(balls[2], balls[4], k=5),
-        Spring(balls[3], balls[4], k=5)
+        Spring(balls[3], balls[4], k=5),
+        Spring(balls[3], balls[5], k=.1, color=(255, 0, 0)),
+        Spring(balls[2], balls[6], k=.1, color=(255, 0, 0))
     ]
 
     while running:
@@ -60,7 +73,9 @@ if __name__ == '__main__':
 
         screen.fill((0, 0, 0))
         physics()
+        physics()
         boost()
+        modulate()
         draw()
 
         pygame.display.flip()
diff --git a/verlet.py b/verlet.py
index 73c554b..4485d22 100644
--- a/verlet.py
+++ b/verlet.py
@@ -45,17 +45,18 @@ class Ball(object):
 
 
 class Spring(object):
-    def __init__(self, a, b, length=None, k=0.3):
+    def __init__(self, a, b, length=None, k=0.3, color=WHITE):
         self.a = a
         self.b = b
         self.k = k
         self.length = self.compute_length() if length is None else length
+        self.color = color
         print(self.length)
 
     def render(self, screen):
         x1, y1 = self.a.pos + CENTER
         x2, y2 = self.b.pos + CENTER
-        pygame.draw.line(screen, WHITE, [x1, y1], [x2, y2])
+        pygame.draw.line(screen, self.color, [x1, y1], [x2, y2])
 
     def compute_length(self):
         x1, y1 = self.a.pos + CENTER
@@ -69,5 +70,3 @@ class Spring(object):
         stretch = (current_length - self.length) / self.length
         self.a.velocity += stretch * delta * self.k
         self.b.velocity -= stretch * delta * self.k
-
-