diff --git a/nhf/build.py b/nhf/build.py
index 3db9c36..106577c 100644
--- a/nhf/build.py
+++ b/nhf/build.py
@@ -69,8 +69,13 @@ class Target:
         else:
             return None
 
-    def write_to(self, obj, path: str):
+    def write_to(self, obj, path: str) -> bool:
+        """
+        Returns false if target is `None`
+        """
         x = self._method(obj)
+        if x is None:
+            return False
         if self.kind == TargetKind.STL:
             assert isinstance(x, Union[
                 Cq.Workplane, Cq.Shape, Cq.Compound, Cq.Assembly])
@@ -92,6 +97,7 @@ class Target:
             Cq.exporters.exportDXF(x, path, **self.kwargs)
         else:
             assert False, f"Invalid kind: {self.kind}"
+        return True
 
     @classmethod
     def methods(cls, subject):
@@ -257,8 +263,9 @@ class Model:
         """
         total = 0
         for t in Target.methods(self).values():
-            t(self)
-            total += 1
+            result = t(self)
+            if result:
+                total += 1
         for t in Assembly.methods(self).values():
             t.check(self)
             total += 1
@@ -288,8 +295,8 @@ class Model:
                 print(f"{Fore.BLUE}Building{Style.RESET_ALL} {output_file}")
 
             try:
-                t.write_to(self, str(output_file))
-                if verbose >= 1:
+                flag = t.write_to(self, str(output_file))
+                if flag and verbose >= 1:
                     print(f"{Fore.GREEN}Built{Style.RESET_ALL} {output_file}")
             except Exception as e:
                 print(f"{Fore.RED}Failed to build{Style.RESET_ALL} {output_file}: {e}")
diff --git a/nhf/touhou/houjuu_nue/joints.py b/nhf/touhou/houjuu_nue/joints.py
index c368d60..5a79461 100644
--- a/nhf/touhou/houjuu_nue/joints.py
+++ b/nhf/touhou/houjuu_nue/joints.py
@@ -16,7 +16,7 @@ TOL = 1e-6
 
 # uxcell 2 Pcs Star Knobs Grips M12 x 30mm Male Thread Steel Zinc Stud Replacement PP
 HS_JOINT_KNOB = ThreaddedKnob(
-    mass=float('nan'),
+    mass=0.0, # FIXME: Measure
     diam_thread=12.0,
     height_thread=30.0,
     diam_knob=50.0,
@@ -36,11 +36,11 @@ HS_JOINT_HEX_NUT = HexNut(
 )
 SHOULDER_AXIS_BOLT = FlatHeadBolt(
     # FIXME: measure
+    mass=0.0,
     diam_head=10.0,
     height_head=3.0,
     diam_thread=6.0,
     height_thread=20.0,
-    mass=float('nan'),
 )
 # Hoypeyfiy 10 Pieces Torsion Spring Woodworking DIY 90 Degrees Torsional
 # Springs Repair Maintenance Spring
diff --git a/nhf/touhou/houjuu_nue/wing.py b/nhf/touhou/houjuu_nue/wing.py
index 27c4c6e..82ed569 100644
--- a/nhf/touhou/houjuu_nue/wing.py
+++ b/nhf/touhou/houjuu_nue/wing.py
@@ -62,7 +62,7 @@ class WingProfile(Model):
         child_arm_radius=23.0,
         parent_arm_radius=30.0,
         hole_diam=4.0,
-        angle_neutral=30.0,
+        angle_neutral=-20.0,
     ))
     # Distance between the two spacers on the elbow, halved
     wrist_h2: float = 5.0
@@ -80,10 +80,10 @@ class WingProfile(Model):
     wrist_bot_loc: Cq.Location
     wrist_height: float
     elbow_rotate: float = -5.0
-    wrist_rotate: float = 30.0
+    wrist_rotate: float = -20.0
 
     # False for the right side, True for the left side
-    flip: bool = False
+    flip: bool
 
     def __post_init__(self):
         super().__init__(name=self.name)
@@ -91,7 +91,10 @@ class WingProfile(Model):
         self.elbow_top_loc = self.elbow_bot_loc * Cq.Location.from2d(0, self.elbow_height)
         self.wrist_top_loc = self.wrist_bot_loc * Cq.Location.from2d(0, self.wrist_height)
         self.elbow_axle_loc = self.elbow_bot_loc * Cq.Location.from2d(0, self.elbow_height / 2)
-        self.wrist_axle_loc = self.wrist_bot_loc * Cq.Location.from2d(0, self.wrist_height / 2)
+        if self.flip:
+            self.wrist_axle_loc = self.wrist_bot_loc * Cq.Location.from2d(0, self.wrist_height / 2)
+        else:
+            self.wrist_axle_loc = self.wrist_bot_loc
 
         assert self.elbow_joint.total_thickness < min(self.s1_thickness, self.s2_thickness)
         assert self.wrist_joint.total_thickness < min(self.s2_thickness, self.s3_thickness)
@@ -329,6 +332,12 @@ class WingProfile(Model):
         """
         Generates profile from shoulder and above. Subclass should implement
         """
+    @target(name="profile-s3-extra", kind=TargetKind.DXF)
+    def profile_s3_extra(self) -> Optional[Cq.Sketch]:
+        """
+        Extra element to be glued on s3. Not needed for left side
+        """
+        return None
 
     def _elbow_joint_retract_cut_polygon(self, loc: Cq.Location) -> Cq.Sketch:
         """
@@ -351,10 +360,15 @@ class WingProfile(Model):
                 for p in points
             ])
         )
-    def _wrist_joint_retract_cut_polygon(self, loc: Cq.Location) -> Cq.Sketch:
+    def _wrist_joint_retract_cut_polygon(self, loc: Cq.Location) -> Optional[Cq.Sketch]:
         """
         Creates a cutting polygon for removing the contraction part of a joint
         """
+        if not self.flip:
+            """
+            No cutting needed on RHS
+            """
+            return None
         theta = math.radians(self.wrist_joint.motion_span)
         dx = self.wrist_height * math.tan(theta)
         dy = self.wrist_height
@@ -521,10 +535,14 @@ class WingProfile(Model):
             .reset()
             .push([self.elbow_axle_loc])
             .each(self._elbow_joint_retract_cut_polygon, mode='s')
-            .reset()
-            .push([self.wrist_axle_loc])
-            .each(self._wrist_joint_retract_cut_polygon, mode='s')
         )
+        if self.flip:
+            profile = (
+                profile
+                .reset()
+                .push([self.wrist_axle_loc])
+                .each(self._wrist_joint_retract_cut_polygon, mode='s')
+            )
         return profile
     def surface_s2(self, front: bool = True) -> Cq.Workplane:
         h = self.elbow_height / 2
@@ -595,7 +613,6 @@ class WingProfile(Model):
         return profile
     def surface_s3(self,
                    front: bool = True) -> Cq.Workplane:
-        h = self.wrist_height / 2
         loc_wrist = Cq.Location.rot2d(self.wrist_rotate) * self.wrist_joint.child_arm_loc(flip=not self.flip)
         tags = [
             ("wrist_bot", self.wrist_axle_loc * loc_wrist *
@@ -605,6 +622,19 @@ class WingProfile(Model):
         ]
         profile = self.profile_s3()
         return extrude_with_markers(profile, self.panel_thickness, tags, reverse=front)
+    def surface_s3_extra(self,
+                         front: bool = True) -> Optional[Cq.Workplane]:
+        profile = self.profile_s3_extra()
+        if profile is None:
+            return None
+        loc_wrist = Cq.Location.rot2d(self.wrist_rotate) * self.wrist_joint.child_arm_loc(flip=not self.flip)
+        tags = [
+            ("wrist_bot", self.wrist_axle_loc * loc_wrist *
+             Cq.Location.from2d(0, self.wrist_h2)),
+            ("wrist_top", self.wrist_axle_loc * loc_wrist *
+             Cq.Location.from2d(0, -self.wrist_h2)),
+        ]
+        return extrude_with_markers(profile, self.panel_thickness, tags, reverse=not front)
     @submodel(name="spacer-s3-wrist")
     def spacer_s3_wrist(self) -> MountingBox:
         return self.spacer_of_joint(
@@ -624,6 +654,18 @@ class WingProfile(Model):
             .constrain("front@faces@>Z", "back@faces@<Z", "Point",
                        param=self.s1_thickness)
         )
+        if not self.flip:
+            (
+                result
+                .addS(self.surface_s3_extra(front=True), name="extra_front",
+                      material=self.mat_panel, role=self.role_panel)
+                .constrain("front?wrist_bot", "extra_front?wrist_bot", "Plane")
+                .constrain("front?wrist_top", "extra_front?wrist_top", "Plane")
+                .addS(self.surface_s3_extra(front=False), name="extra_back",
+                      material=self.mat_panel, role=self.role_panel)
+                .constrain("back?wrist_bot", "extra_back?wrist_bot", "Plane")
+                .constrain("back?wrist_top", "extra_back?wrist_top", "Plane")
+            )
         for t in ["wrist_bot", "wrist_top"]:
             is_top = t.endswith("_top")
             o = self.spacer_s3_wrist()
@@ -756,10 +798,22 @@ class WingR(WingProfile):
     arrow_height: float = 300
     arrow_angle: float = -8
 
+    # Underapproximate the wrist tangent angle to leave no gaps on the blade
+    blade_wrist_approx_tangent_angle: float = 40.0
+    blade_overlap_arrow_height: float = 5.0
+    # Some overlap needed to glue the two sides
+    blade_overlap_angle: float = -1
+    blade_hole_angle: float = 3
+    blade_hole_diam: float = 12.0
+    blade_hole_heights: list[float] = field(default_factory=lambda: [230, 260])
+    blade_angle: float = 7
+
     # Relative (in wrist coordinate) centre of the ring
     ring_rel_loc: Cq.Location = Cq.Location.from2d(45.0, 25.0)
     ring_radius_inner: float = 22.0
 
+    flip: bool = False
+
     def __post_init__(self):
         super().__post_init__()
         assert self.arrow_angle < 0, "Arrow angle cannot be positive"
@@ -771,6 +825,10 @@ class WingR(WingProfile):
         self.ring_loc = self.wrist_top_loc * self.ring_rel_loc
         assert self.ring_radius > self.ring_radius_inner
 
+        assert 0 > self.blade_overlap_angle > self.arrow_angle
+        assert 0 < self.blade_hole_angle < self.blade_angle
+        assert self.blade_wrist_approx_tangent_angle <= self.wrist_bot_loc.to2d_rot()
+
     @property
     def ring_radius(self) -> float:
         (dx, dy), _ = self.ring_rel_loc.to2d()
@@ -829,6 +887,43 @@ class WingR(WingProfile):
         )
         return result
 
+    def profile_s3_extra(self) -> Cq.Sketch:
+        """
+        Implements the blade part on Nue's wing
+        """
+        left_bot_loc = self.arrow_bot_loc * Cq.Location.rot2d(-1)
+        hole_bot_loc = self.arrow_bot_loc * Cq.Location.rot2d(self.blade_hole_angle)
+        right_bot_loc = self.arrow_bot_loc * Cq.Location.rot2d(self.blade_angle)
+        h_loc = Cq.Location.from2d(0, self.arrow_height + self.blade_overlap_arrow_height)
+
+        # Law of sines, uses the triangle of (wrist_bot_loc, arrow_bot_loc, ?)
+        theta_wp = math.radians(90 - self.blade_wrist_approx_tangent_angle)
+        theta_b = math.radians(self.blade_angle)
+        h_blade = math.sin(theta_wp) / math.sin(math.pi - theta_b - theta_wp) * self.arrow_height
+        h_blade_loc = Cq.Location.from2d(0, h_blade)
+        return (
+            Cq.Sketch()
+            .segment(
+                self.arrow_bot_loc.to2d_pos(),
+                (left_bot_loc * h_loc).to2d_pos(),
+            )
+            .segment(
+                (self.arrow_bot_loc * h_loc).to2d_pos(),
+            )
+            .segment(
+                (right_bot_loc * h_blade_loc).to2d_pos(),
+            )
+            .close()
+            .assemble()
+            .reset()
+            .push([
+                (hole_bot_loc * Cq.Location.from2d(0, h)).to2d_pos()
+                for h in self.blade_hole_heights
+            ])
+            .circle(self.blade_hole_diam / 2, mode='s')
+        )
+
+
     def _mask_elbow(self) -> list[Tuple[float, float]]:
         l = 200
         elbow_x, _ = self.elbow_bot_loc.to2d_pos()
diff --git a/nhf/utils.py b/nhf/utils.py
index e999e85..3399fce 100644
--- a/nhf/utils.py
+++ b/nhf/utils.py
@@ -72,7 +72,7 @@ def to2d_pos(self: Cq.Location) -> Tuple[float, float]:
     return x, y
 Cq.Location.to2d_pos = to2d_pos
 
-def to2d_rot(self: Cq.Location) -> Tuple[float, float]:
+def to2d_rot(self: Cq.Location) -> float:
     """
     Returns position and angle
     """