diff --git a/009-Extrusion/box.scad b/009-Extrusion/box.scad
new file mode 100644
index 0000000..59439e6
--- /dev/null
+++ b/009-Extrusion/box.scad
@@ -0,0 +1,32 @@
+$fa=0.5;
+$fs=0.2;
+
+module rounded_rectangle(l, w, r) {
+  union() {
+    square([l-2*r, w], center=true);
+    square([l, w-2*r], center=true);
+    translate([l/2-r, w/2-r]) circle(r=r);
+    translate([-l/2+r, w/2-r]) circle(r=r);
+    translate([-l/2+r, -w/2+r]) circle(r=r);
+    translate([l/2-r, -w/2+r]) circle(r=r);
+  }
+}
+
+module box(l, w, h, r, thickness) {
+  difference() {
+    scale([1,1,-1])
+      linear_extrude(height=h)
+        rounded_rectangle(l, w, r);
+    scale([1,1,-1])
+      translate([0,0,-thickness])
+      linear_extrude(height=h)
+        rounded_rectangle(l-thickness*2, w-thickness*2, r);
+  }
+}
+
+// Small box
+box(10, 20, 10, 1, 1);
+
+// Bigger box
+translate([30, 30, 0])
+  box(15, 15, 5, 3, 0.5);