Split lib files

lib/extension.scad

@@ -0,0 +1,27 @@
+use <spoolmount_a.scad>
+use <spoolmount_b.scad>
+
+module extension(h) {
+    assert(h >= 23, "minimum extension height is 23");
+
+    // Bottom spoolmount
+    spoolmount_b();
+
+    // Top spoolmount
+    translate([0, 0, h - 5])
+    spoolmount_a();
+
+    // Center cylinder
+    cylinder(h=h, r=29, $fn=200);
+
+    // Expansion to support top spoolmount
+    translate([0, 0, h - 18])
+    rotate_extrude($fn=200)
+    polygon(points=[
+        [29, 0],
+        [42, 13],
+        [29, 13],
+    ]);
+}
+
+extension(h=25);