diff --git a/nhf/touhou/houjuu_nue/wing.py b/nhf/touhou/houjuu_nue/wing.py
index bc1c690..69cadaa 100644
--- a/nhf/touhou/houjuu_nue/wing.py
+++ b/nhf/touhou/houjuu_nue/wing.py
@@ -36,8 +36,10 @@ class WingProfile(Model):
     shoulder_width: float = 36.0
     shoulder_tip_x: float = -260.0
     shoulder_tip_y: float = 165.0
-    shoulder_mid_x: float = -125.0
-    shoulder_mid_y: float = 75.0
+    shoulder_tip_bezier_x: float = 100.0
+    shoulder_tip_bezier_y: float = -50.0
+    shoulder_base_bezier_x: float = -30.0
+    shoulder_base_bezier_y: float = 30.0
 
     s0_hole_loc: Cq.Location = Cq.Location.from2d(-25, 33)
     s0_hole_diam: float = 15.0
@@ -153,8 +155,7 @@ class WingProfile(Model):
 
     def outer_profile_s0(self) -> Cq.Sketch:
         """
-        The outer boundary of s0, used to produce the curved panel and the
-        top/bottom slots
+        The outer boundary of s0 top/bottom slots
         """
         tip_x = self.shoulder_tip_x
         tip_y = self.shoulder_tip_y
@@ -170,15 +171,35 @@ class WingProfile(Model):
             #    (tip_x - 10, tip_y),
             #)
         )
+    def inner_profile_s0(self) -> Cq.Edge:
+        """
+        The inner boundary of s0
+        """
+        tip_x = self.shoulder_tip_x
+        tip_y = self.shoulder_tip_y
+        dx2 = self.shoulder_tip_bezier_x
+        dy2 = self.shoulder_tip_bezier_y
+        dx1 = self.shoulder_base_bezier_x
+        dy1 = self.shoulder_base_bezier_y
+        sw = self.shoulder_width
+        return Cq.Edge.makeBezier(
+            [
+                Cq.Vector(*p)
+                for p in [
+                        (tip_x, tip_y - sw),
+                        (tip_x + dx2, tip_y - sw + dy2),
+                        (-self.base_width + dx1, dy1),
+                        (-self.base_width, 0),
+                ]
+            ]
+        )
 
     @property
     def shoulder_angle_neutral(self) -> float:
         """
         Returns the neutral angle of the shoulder
         """
-        dx = self.shoulder_mid_x - self.shoulder_tip_x
-        dy = -(self.shoulder_mid_y - (self.shoulder_tip_y - self.shoulder_width))
-        result = math.degrees(math.atan2(dy, dx))
+        result = math.degrees(math.atan2(-self.shoulder_tip_bezier_y, self.shoulder_tip_bezier_x))
         assert result >= 0
         return result
 
@@ -186,8 +207,10 @@ class WingProfile(Model):
     def profile_s0(self, top: bool = True) -> Cq.Sketch:
         tip_x = self.shoulder_tip_x
         tip_y = self.shoulder_tip_y
-        mid_x = self.shoulder_mid_x
-        mid_y = self.shoulder_mid_y
+        dx2 = self.shoulder_tip_bezier_x
+        dy2 = self.shoulder_tip_bezier_y
+        dx1 = self.shoulder_base_bezier_x
+        dy1 = self.shoulder_base_bezier_y
         sw = self.shoulder_width
         sketch = (
             self.outer_profile_s0()
@@ -196,14 +219,12 @@ class WingProfile(Model):
                 (tip_x, tip_y),
                 (tip_x, tip_y - sw),
             )
-            .segment(
+            .bezier([
                 (tip_x, tip_y - sw),
-                (mid_x, mid_y),
-            )
-            .segment(
-                (mid_x, mid_y),
+                (tip_x + dx2, tip_y - sw + dy2),
+                (-self.base_width + dx1, dy1),
                 (-self.base_width, 0),
-            )
+            ])
             .assemble()
             .push([self.shoulder_axle_loc.to2d_pos()])
             .circle(self.shoulder_joint.radius, mode='a')
@@ -231,6 +252,18 @@ class WingProfile(Model):
         plane.moveTo(0, 0).tagPlane("bot")
         plane.moveTo(0, self.root_height + t*2).tagPlane("top")
         return result
+    def inner_shell_s0(self) -> Cq.Workplane:
+        t = self.panel_thickness
+        #profile = Cq.Wire.assembleEdges(self.inner_profile_s0())
+        result = (
+            Cq.Workplane('XZ')
+            .rect(t, self.root_height + t*2, centered=(False, False))
+            .sweep(self.inner_profile_s0())
+        )
+        plane = result.copyWorkplane(Cq.Workplane('XZ'))
+        plane.moveTo(t, 0).tagPlane("bot")
+        plane.moveTo(t, self.root_height + t*2).tagPlane("top")
+        return result
 
     @submodel(name="spacer-s0-shoulder")
     def spacer_s0_shoulder(self) -> MountingBox:
@@ -318,6 +351,7 @@ class WingProfile(Model):
         )
         h = self.panel_thickness if top else 0
         result.copyWorkplane(Cq.Workplane('XZ')).moveTo(0, h).tagPlane("corner")
+        result.copyWorkplane(Cq.Workplane('XZ')).moveTo(-self.base_width, h).tagPlane("corner_left")
         return result
 
     @assembly()
@@ -331,12 +365,16 @@ class WingProfile(Model):
                   loc=Cq.Location((0, 0, self.root_height + self.panel_thickness)))
             .constrain("bot", "Fixed")
             .constrain("top", "Fixed")
-            #.constrain("bot@faces@>Z", "top@faces@<Z", "Point",
-            #           param=self.shoulder_joint.height)
+            .constrain("bot@faces@>Z", "top@faces@<Z", "Point",
+                       param=self.shoulder_height)
             .addS(self.outer_shell_s0(), name="outer_shell",
                   material=self.mat_panel, role=self.role_panel)
             .constrain("bot?corner", "outer_shell?bot", "Plane", param=0)
             .constrain("top?corner", "outer_shell?top", "Plane", param=0)
+            #.addS(self.inner_shell_s0(), name="inner_shell",
+            #      material=self.mat_panel, role=self.role_panel)
+            #.constrain("bot?corner_left", "inner_shell?bot", "Point")
+            #.constrain("top?corner_left", "inner_shell?top", "Point")
         )
         for o, tag in [
                 (self.spacer_s0_shoulder().generate(), "shoulder"),