diff --git a/boxes/generators/atreus21.py b/boxes/generators/atreus21.py
index 5dc604c..8d7ac1a 100644
--- a/boxes/generators/atreus21.py
+++ b/boxes/generators/atreus21.py
@@ -4,13 +4,14 @@ from copy import deepcopy
 
 from boxes import Boxes, Color, holeCol, restore, boolarg
 from boxes.edges import FingerJointSettings
+from .keyboard import Keyboard
 
 
-class Atreus21(Boxes):
+class Atreus21(Boxes, Keyboard):
     """Generator for a split atreus keyboard."""
     ui_group = 'Misc'
     btn_size = 15.6
-    btn_outer = btn_size + 3.4
+    half_btn = btn_size / 2
     border = 6
 
     row_offsets=[3, 6, 11, 5, 0, btn_size * .5]
@@ -82,73 +83,36 @@ class Atreus21(Boxes):
         corner = [90, b]
         self.polyline(*([x, corner, y, corner] * 2))
         self.moveTo(0, b)
-    
-    def half(self, cb=None, reverse=False):
+
+    def half(self, hole_cb=None, reverse=False):
         row_offsets=self.row_offsets
         row_keys=self.row_keys
         scheme = list(zip(row_offsets, row_keys))
-        if reverse:
-            scheme.reverse()
-        for offset, keys in scheme:
-            self.moveTo(0, offset)
-            self.key_row(keys, cb)
-            self.moveTo(self.btn_outer)
-            self.moveTo(0, -offset)
-
-        total_moved_rows = len(row_offsets) * (self.btn_outer)
-        self.moveTo(total_moved_rows * -1, 0)
-
-    def key_row(self, n, hole_cb=None):
-        """Callback for the key holes."""
         if hole_cb == None:
             hole_cb = self.key
-        for _ in range(n):
-            hole_cb()
-        self.moveTo(0, -n * (self.btn_outer))
+        self.moveTo(self.half_btn, self.half_btn)
+        self.apply_callback_on_columns(
+            hole_cb,
+            scheme,
+            self.STANDARD_KEY_SPACING,
+            reverse,
+        )
+        self.moveTo(-self.half_btn, -self.half_btn)
 
     def support(self):
-        btn = [11.6, (-90, 2)] * 4
-        self.set_source_color(Color.BLUE)
-        self.moveTo(0, 2, 90)
-        self.polyline(*btn)
-        self.moveTo(-2, 0, 270)
-        self.moveTo(0, self.btn_outer)
-        self.set_source_color(Color.BLACK)
+        self.outer_hole()
 
     def hotplug(self):
-        self.moveTo(7.8 , 7.8)
-        self.hole(0, 0, d=4)
-        self.hole(1.27 * -3, 1.27 * 2, d=2.9)
-        self.hole(1.27 * 2, 1.27 * 4, d=2.9)
-
-        # pcb mounts
-        self.hole(1.27 * -4, 0, d=1.7)
-        self.hole(1.27 * 4, 0, d=1.7)
-
-        self.moveTo(-7.8, -7.8)
-        self.moveTo(0, self.btn_outer)
+        self.pcb_holes()
 
     def key(self):
-        self.set_source_color(Color.BLUE)
-
-        # draw clock wise to work with burn correction
-        btn_half_side = [0.98, 90, 0.81, -90, 3.5, -90, 0.81, 90, 2.505]
-        btn_full_side = [*btn_half_side, 0, *btn_half_side[::-1]]
-        btn = [*btn_full_side, -90] * 4
-
-        self.moveTo(0.81, 0.81, 90)
-        self.polyline(*btn)
-        self.moveTo(0, 0, 270)
-        self.moveTo(-0.81, -0.81)
-        self.moveTo(0, self.btn_outer)
-
-        self.set_source_color(Color.BLACK)
+        self.castle_shaped_plate_cutout()
 
     # get case sizes
     def _case_x_y(self):
-        x = len(self.row_offsets) * self.btn_outer - 4
+        x = len(self.row_offsets) * self.STANDARD_KEY_SPACING - 4
         y = sum([
-            max(self.row_keys) * self.btn_outer,  # total button sizes
+            max(self.row_keys) * self.STANDARD_KEY_SPACING,  # total button sizes
             max(self.row_offsets),  # offset of highest row
             -4,
         ])
diff --git a/boxes/generators/keyboard.py b/boxes/generators/keyboard.py
new file mode 100644
index 0000000..2b8e0e2
--- /dev/null
+++ b/boxes/generators/keyboard.py
@@ -0,0 +1,105 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# Copyright (C) 2021 Guillaume Collic
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+class Keyboard:
+    """
+    Code to manage Cherry MX compatible switches and Kailh hotswap socket.
+    """
+
+    STANDARD_KEY_SPACING = 19
+    SWITCH_CASE_SIZE = 15.6
+
+    def __init__(self):
+        pass
+
+    def pcb_holes(self):
+        grid_unit = 1.27
+        main_hole_size = 4
+        pcb_mount_size = 1.7
+        led_hole_size = 1
+        pin_hole_size = 2.9
+
+        def grid_hole(x, y, d):
+            self.hole(grid_unit * x, grid_unit * y, d=d)
+
+        # main hole
+        grid_hole(0, 0, main_hole_size)
+
+        # switch pins
+        grid_hole(-3, 2, pin_hole_size)
+        grid_hole(2, 4, pin_hole_size)
+
+        grid_hole(-4, 0, pcb_mount_size)
+        grid_hole(4, 0, pcb_mount_size)
+
+    def apply_callback_on_columns(self, cb, columns_definition, spacing, reverse=False):
+        if reverse:
+            columns_definition = list(reversed(columns_definition))
+
+        for offset, nb_keys in columns_definition:
+            self.moveTo(0, offset)
+            for _ in range(nb_keys):
+                cb()
+                self.moveTo(0, spacing)
+            self.moveTo(spacing, -nb_keys * spacing)
+            self.moveTo(0, -offset)
+
+        total_width = len(columns_definition) * spacing
+        self.moveTo(-1 * total_width)
+
+    def outer_hole(self, radius=2, centered=True):
+        """
+        Draws a rounded square big enough to go around a whole switch (15.6mm)
+        """
+        half_size = Keyboard.SWITCH_CASE_SIZE / 2
+        if centered:
+            self.moveTo(-half_size, -half_size)
+
+        # draw clock wise to work with burn correction
+        straight_edge = Keyboard.SWITCH_CASE_SIZE - 2 * radius
+        polyline = [straight_edge, (-90, radius)] * 4
+        self.moveTo(0, radius, 90)
+        self.polyline(*polyline)
+        self.moveTo(0, 0, 270)
+        self.moveTo(0, -radius)
+        self.moveTo(0)
+
+        if centered:
+            self.moveTo(half_size, half_size)
+
+    def castle_shaped_plate_cutout(self, centered=True):
+        """
+        This cutout shaped like a castle enables switch modding and rotation.
+        More information (type 4) on https://geekhack.org/index.php?topic=59837.0
+        """
+        half_size = Keyboard.SWITCH_CASE_SIZE / 2
+        if centered:
+            self.moveTo(-half_size, -half_size)
+
+        # draw clock wise to work with burn correction
+        btn_half_side = [0.98, 90, 0.81, -90, 3.5, -90, 0.81, 90, 2.505]
+        btn_full_side = [*btn_half_side, 0, *btn_half_side[::-1]]
+        btn = [*btn_full_side, -90] * 4
+
+        self.moveTo(0.81, 0.81, 90)
+        self.polyline(*btn)
+        self.moveTo(0, 0, 270)
+        self.moveTo(-0.81, -0.81)
+
+        if centered:
+            self.moveTo(half_size, half_size)
\ No newline at end of file
diff --git a/boxes/generators/keypad.py b/boxes/generators/keypad.py
index 372a07b..d16f890 100644
--- a/boxes/generators/keypad.py
+++ b/boxes/generators/keypad.py
@@ -4,13 +4,16 @@ from copy import deepcopy
 
 from boxes import Boxes, boolarg
 from boxes.edges import FingerJointSettings
+from .keyboard import Keyboard
 
 
-class Keypad(Boxes):
+class Keypad(Boxes, Keyboard):
     """Generator for keypads with mechanical switches."""
     ui_group = 'Box'
     btn_size = 15.6
-    triangle = 25.
+    space_between_btn = 4
+    box_padding = 10
+    triangle = 25.0
 
     def __init__(self):
         super().__init__()
@@ -45,8 +48,8 @@ class Keypad(Boxes):
 
     def _get_x_y(self):
         """Gets the keypad's size based on the number of buttons."""
-        x = self.btn_x * (self.btn_size) + (self.btn_x - 1) * 4 + 20
-        y = self.btn_y * (self.btn_size) + (self.btn_y - 1) * 4 + 20
+        x = self.btn_x * (self.btn_size) + (self.btn_x - 1) * self.space_between_btn + 2*self.box_padding
+        y = self.btn_y * (self.btn_size) + (self.btn_y - 1) * self.space_between_btn + 2*self.box_padding
         return x, y
 
     def render(self):
@@ -69,10 +72,10 @@ class Keypad(Boxes):
         self.rectangularWall(x, h, "GFEF", callback=[self.wallx_cb], move="left up")
 
         # keypad lids
-        self.rectangularWall(x, y, "ffff", callback=[self.support_hole], move="right")
-        self.rectangularWall(x, y, "ffff", callback=[self.key_hole], move="up")
+        self.rectangularWall(x, y, "ffff", callback=self.to_grid_callback(self.support_hole), move="right")
+        self.rectangularWall(x, y, "ffff", callback=self.to_grid_callback(self.key_hole), move="up")
         if self.top2_enable:
-            self.rectangularWall(x, y, "ffff", callback=[self.hotplug])
+            self.rectangularWall(x, y, "ffff", callback=self.to_grid_callback(self.hotplug))
 
         # screwable
         tr = self.triangle
@@ -87,64 +90,27 @@ class Keypad(Boxes):
             callback=[None, lambda: self.hole(trh, trh, d=d1)]
         )
 
+    def to_grid_callback(self, inner_callback):
+        scheme = [(0, self.btn_y)]*self.btn_x
+        def callback():
+            # move to first key center
+            key_margin = self.box_padding + self.btn_size / 2
+            self.moveTo(key_margin, key_margin)
+            self.apply_callback_on_columns(
+                inner_callback, scheme, self.btn_size + self.space_between_btn
+            )
+
+        return [callback]
 
     def hotplug(self):
         """Callback for the key stabelizers."""
-        # draw clock wise to work with burn correction
-        btn = [11.6, (-90, 2)] * 4
-        s = self.btn_size
-        self.moveTo(10, 10)
-        for _ in range(self.btn_y):
-            for _ in range(self.btn_x):
-                self.moveTo(7.8 , 7.8)
-
-                self.hole(0, 0, d=4)
-                self.hole(1.27 * -3, 1.27 * 2, d=2.9)
-                self.hole(1.27 * 2, 1.27 * 4, d=2.9)
-
-                # pcb mounts
-                self.hole(1.27 * -4, 0, d=1.7)
-                self.hole(1.27 * 4, 0, d=1.7)
-
-                self.moveTo(-7.8, -7.8)
-                self.moveTo(s + 4)
-
-                #self.moveTo(1.27 * -2, 1.17 * 3)
-                #self.moveTo(1.27 * 2, 1.17 * -3)
-            self.moveTo(self.btn_x * (s + 4) * -1, s + 4)
+        self.pcb_holes()
 
     def support_hole(self):
-        """Callback for the key stabelizers."""
-        # draw clock wise to work with burn correction
-        btn = [11.6, (-90, 2)] * 4
-
-        s = self.btn_size
-        self.moveTo(10, 10)
-        for _ in range(self.btn_y):
-            for _ in range(self.btn_x):
-                self.moveTo(0, 2, 90)
-                self.polyline(*btn)
-                self.moveTo(0, 0, 270)
-                self.moveTo(s + 4, -2)
-            self.moveTo(self.btn_x * (s + 4) * -1, s + 4)
+        self.outer_hole()
 
     def key_hole(self):
-        """Callback for the key holes."""
-        # draw clock wise to work with burn correction
-        btn_half_side = [0.98, 90, 0.81, -90, 3.5, -90, 0.81, 90, 2.505]
-        btn_full_side = [*btn_half_side, 0, *btn_half_side[::-1]]
-        btn = [*btn_full_side, -90] * 4
-
-        s = self.btn_size
-        self.moveTo(10, 10)
-        for _ in range(self.btn_y):
-            for _ in range(self.btn_x):
-                self.moveTo(0.81, 0.81, 90)
-                self.polyline(*btn)
-                self.moveTo(0, 0, 270)
-                self.moveTo(-0.81, -0.81)
-                self.moveTo(s + 4)
-            self.moveTo(self.btn_x * (s + 4) * -1, s + 4)
+        self.castle_shaped_plate_cutout()
 
     # stolen form electronics-box
     def wallx_cb(self):