diff --git a/.gitignore b/.gitignore
index 3311046..1cc3bdb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,4 @@ dist
 *.egg-info
 *~
 *.png
+*.swp
diff --git a/daft.py b/daft.py
index dd27d07..942ed3c 100644
--- a/daft.py
+++ b/daft.py
@@ -155,8 +155,13 @@ class Node(object):
     :param aspect: (optional)
         The aspect ratio width/height for elliptical nodes; default 1.
 
-    :param observed: (optional)
-        Should this be a conditioned variable?
+    :param rectangle: (optional)
+        If `True` node has a rectangular shape.
+
+    :param double: (optional)
+        Double lines. This must be ``"inner"`` or ``"outer"``.
+        Node is shown as double shapes with the second shape plotted inside
+        or outside of the standard one, respectively.
 
     :param fixed: (optional)
         Should this be a fixed (not permitted to vary) variable?
@@ -174,13 +179,16 @@ class Node(object):
 
     """
     def __init__(self, name, content, x, y, scale=1, aspect=None,
-                 observed=False, fixed=False,
+                 observed=False, fixed=False, rectangle=False,
+                 double = "",
                  offset=[0, 0], plot_params={}, label_params=None):
         # Node style.
         assert not (observed and fixed), \
             "A node cannot be both 'observed' and 'fixed'."
         self.observed = observed
         self.fixed = fixed
+        self.rectangle = rectangle
+        self.double = double
 
         # Metadata.
         self.name = name
@@ -256,23 +264,28 @@ def render(self, ctx):
             aspect = ctx.aspect
 
         # Set up an observed node. Note the fc INSANITY.
-        if self.observed:
+        if self.observed or self.double =="inner" or self.double=="outer":
             # Update the plotting parameters depending on the style of
             # observed node.
             h = float(diameter)
             w = aspect * float(diameter)
-            if ctx.observed_style == "shaded":
+            if ctx.observed_style == "shaded" and self.observed:
                 p["fc"] = "0.7"
-            elif ctx.observed_style == "outer":
+            elif ctx.observed_style == "outer" or self.double == "outer":
                 h = diameter + 0.1 * diameter
                 w = aspect * diameter + 0.1 * diameter
-            elif ctx.observed_style == "inner":
+            elif ctx.observed_style == "inner" or self.double == "inner":
                 h = diameter - 0.1 * diameter
                 w = aspect * diameter - 0.1 * diameter
                 p["fc"] = fc
 
             # Draw the background ellipse.
-            bg = Ellipse(xy=ctx.convert(self.x, self.y),
+            if self.rectangle:
+                xy = np.array(ctx.convert(self.x, self.y)) - diameter/2.0
+                xy = xy + (diameter-w)/float(2)
+                bg = Rectangle(xy=xy, width=w, height=h, **p)
+            else:
+                bg = Ellipse(xy=ctx.convert(self.x, self.y),
                          width=w, height=h, **p)
             ax.add_artist(bg)
 
@@ -280,9 +293,15 @@ def render(self, ctx):
             p["fc"] = fc
 
         # Draw the foreground ellipse.
-        if ctx.observed_style == "inner" and not self.fixed:
+        if ctx.observed_style == "inner" and not self.fixed and \
+            (self.observed or self.double == "inner"):
             p["fc"] = "none"
-        el = Ellipse(xy=ctx.convert(self.x, self.y),
+        if self.rectangle:
+            xy = np.array(ctx.convert(self.x, self.y)) - diameter/2.0
+            el = Rectangle(xy=xy, width=diameter * aspect,
+                     height=diameter, **p)
+        else:
+            el = Ellipse(xy=ctx.convert(self.x, self.y),
                      width=diameter * aspect, height=diameter, **p)
         ax.add_artist(el)
 
@@ -351,9 +370,12 @@ def _get_coords(self, ctx):
         dist1 = np.sqrt(dy * dy + dx * dx / float(a1 ** 2))
         dist2 = np.sqrt(dy * dy + dx * dx / float(a2 ** 2))
 
+        radius1 = 0.5 * ctx.node_unit * self.node1.scale
+        radius2 = 0.5 * ctx.node_unit * self.node2.scale
+
         # Compute the fractional effect of the radii of the nodes.
-        alpha1 = 0.5 * ctx.node_unit * self.node1.scale / dist1
-        alpha2 = 0.5 * ctx.node_unit * self.node2.scale / dist2
+        alpha1 = radius1 / dist1
+        alpha2 = radius2 / dist2
 
         # Get the coordinates of the starting position.
         x0, y0 = x1 + alpha1 * dx, y1 + alpha1 * dy
@@ -362,6 +384,24 @@ def _get_coords(self, ctx):
         dx0 = dx * (1. - alpha1 - alpha2)
         dy0 = dy * (1. - alpha1 - alpha2)
 
+        if self.node1.rectangle or self.node2.rectangle:
+            # calc displacement of the edge (in direction of the edge)
+            length, angle = cart2polar(dx0, dy0)
+            if abs(angle)>np.pi*0.25 and abs(angle)<np.pi*0.75: # upper & lower
+                angle2 = angle - np.pi/2.0
+            else:
+                angle2 = angle
+            displacement = radius1/abs(np.cos(angle2))  - radius1
+
+            if self.node1.rectangle:
+                displacement_xy = polar2cart(displacement, angle)
+                x0 += displacement_xy[0]
+                y0 += displacement_xy[1]
+            if self.node2.rectangle and self.node1.rectangle:
+                dx0, dy0 = polar2cart(length-2*displacement, angle)
+            else:
+                dx0, dy0 = polar2cart(length-displacement, angle)
+
         return x0, y0, dx0, dy0
 
     def render(self, ctx):
@@ -621,3 +661,15 @@ def _pop_multiple(d, default, *args):
         return default
 
     return results[0][1]
+
+def polar2cart(r, theta):
+    """polar coordinates to cartesian coordinates"""
+    x = r  * np.cos(theta)
+    y = r  * np.sin(theta)
+    return x, y
+
+def cart2polar(x,y):
+    """ cartesian coordinates to polar coordinates"""
+    r = np.sqrt(x**2 + y**2)
+    theta = np.arctan2(y, x)
+    return r, theta