diff --git a/cartridge.scad b/cartridge.scad
index d19f507..86c81a4 100644
--- a/cartridge.scad
+++ b/cartridge.scad
@@ -1,5 +1,3 @@
-$fn = $preview ? 32 : 128;
-
 // Cartridge base dimensions
 cartridge_width = 102;
 cartridge_length = 133;
@@ -61,8 +59,6 @@ nfc_coin_depth = 1;
 nfc_coin_diameter = 25;
 nfc_coin_tolerance = 0.1;
 
-cartridge();
-
 module cartridge() {
   difference() {
     base();
@@ -189,37 +185,29 @@ module nfc_coin() {
 
 module footprint() {
   hull() {
-    translate([
-      cartridge_length - back_vertical_fillet_radius,
-      back_vertical_fillet_radius,
-    ]) {
-      circle(back_vertical_fillet_radius);
-      // translate([0, cartridge_width - back_vertical_fillet_radius])
-      //   circle(back_vertical_fillet_radius);
-    }
-    translate([
-      cartridge_length - back_vertical_fillet_radius,
-      cartridge_width - back_vertical_fillet_radius,
-    ]) circle(back_vertical_fillet_radius);
-    translate([
-      tape_guide_depth + side_vertical_fillet_radius * tan(0.5 * atan(tape_guide_slope)),
-      side_vertical_fillet_radius,
-    ]) circle(side_vertical_fillet_radius);
-    translate([
-      tape_guide_depth + side_vertical_fillet_radius * tan(0.5 * atan(tape_guide_slope)),
-      cartridge_width - side_vertical_fillet_radius,
-    ]) circle(side_vertical_fillet_radius);
-    translate([
-      front_vertical_fillet_radius,
-      tape_guide_width + front_vertical_fillet_radius * tan(0.5 * atan(1 / tape_guide_slope)),
-    ]) circle(front_vertical_fillet_radius);
-    translate([
-      front_vertical_fillet_radius,
-      cartridge_width - tape_guide_width - front_vertical_fillet_radius * tan(0.5 * atan(1 / tape_guide_slope)),
-    ]) circle(front_vertical_fillet_radius);
+    one_side_vertical_fillets();
+    translate([0, cartridge_width]) mirror([0, 1]) one_side_vertical_fillets();
   }
 }
 
+module one_side_vertical_fillets() {
+  translate([
+    cartridge_length - back_vertical_fillet_radius,
+    back_vertical_fillet_radius,
+  ])
+    circle(back_vertical_fillet_radius);
+  translate([
+    tape_guide_depth + side_vertical_fillet_radius * tan(0.5 * atan(tape_guide_slope)),
+    side_vertical_fillet_radius,
+  ])
+    circle(side_vertical_fillet_radius);
+  translate([
+    front_vertical_fillet_radius,
+    tape_guide_width + front_vertical_fillet_radius * tan(0.5 * atan(1 / tape_guide_slope)),
+  ])
+    circle(front_vertical_fillet_radius);
+}
+
 module tracks() {
   track_interval = cartridge_width - 2 * track_side_inset;
   translate([track_front_inset, track_side_inset, cartridge_height])
diff --git a/justfile b/justfile
new file mode 100644
index 0000000..9e79d4b
--- /dev/null
+++ b/justfile
@@ -0,0 +1,6 @@
+default: (build "cartridge") (build "receptacle")
+
+build target:
+    echo 'use <{{target}}.scad>; $fn = 128; {{target}}();' > part.scad
+    openscad -o {{target}}.stl part.scad
+    rm part.scad
diff --git a/receptacle.scad b/receptacle.scad
new file mode 100644
index 0000000..7e3fd39
--- /dev/null
+++ b/receptacle.scad
@@ -0,0 +1,93 @@
+include <cartridge.scad>;
+
+cartridge_clearance = 0.3;
+
+module receptacle() {
+  difference() {
+    box();
+    hole();
+    feet_grooves();
+    track_grooves();
+  }
+  tape_guides();
+}
+
+module box() {
+  translate([
+    -5,
+    -cartridge_clearance - 5,
+    -cartridge_clearance - 10,
+  ])
+    cube([
+      cartridge_length + 5 - grip_count * grip_wedge_width - back_vertical_fillet_radius,
+      cartridge_width  + 10,
+      cartridge_height + 20,
+    ]);
+}
+
+module hole() {
+  translate([
+    -cartridge_clearance,
+    -cartridge_clearance,
+    -cartridge_clearance,
+  ])
+    cube([
+      cartridge_length + cartridge_clearance,
+      cartridge_width  + 2 * cartridge_clearance,
+      cartridge_height + 2 * cartridge_clearance,
+    ]);
+}
+
+module feet_grooves() {
+  foot_groove_interval = cartridge_width - 2 * foot_side_inset - foot_width + cartridge_clearance;
+  foot_groove();
+  translate([0, foot_groove_interval]) foot_groove();
+}
+
+module foot_groove() {
+  translate([
+    foot_front_inset - cartridge_clearance,
+    foot_side_inset - cartridge_clearance,
+    -foot_height,
+  ])
+    cube([
+      cartridge_length + 2 * cartridge_clearance,
+      foot_width + cartridge_clearance,
+      foot_height,
+    ]);
+}
+
+module track_grooves() {
+  translate([
+    track_back_inset + cartridge_clearance,
+    0,
+    cartridge_height + cartridge_clearance
+  ])
+    rotate([0, 90, 0]) {
+      translate([0, track_side_inset]) track_groove();
+      translate([0, cartridge_width - track_side_inset]) track_groove();
+    }
+}
+
+module track_groove() {
+  cylinder(
+    h=cartridge_length + cartridge_clearance,
+    r=track_radius + cartridge_clearance,
+  );
+}
+
+module tape_guides() {
+  translate([0, cartridge_width])
+    mirror([0, 1])
+    tape_guide();
+  tape_guide();
+}
+
+module tape_guide() {
+  linear_extrude(cartridge_height + 2 * cartridge_clearance)
+    polygon([
+      [0, 0],
+      [0, tape_guide_width - cartridge_clearance],
+      [tape_guide_depth - cartridge_clearance, 0],
+    ]);
+}