finalized porting examples

examples/key_cap_algebra.py

@@ -0,0 +1,42 @@
+from build123d import *
+
+# Taper Extrude and Extrude to "next" while creating a Cherry MX key cap
+# See: https://www.cherrymx.de/en/dev.html
+
+plan = Rectangle(18 * MM, 18 * MM)
+key_cap = extrude(plan, amount=10 * MM, taper=15)
+
+# Create a dished top
+key_cap -= Location((0, -3 * MM, 47 * MM), (90, 0, 0)) * Sphere(40 * MM)
+
+# Fillet all the edges except the bottom
+key_cap = fillet(
+    *key_cap.edges().filter_by_position(Axis.Z, 0, 30 * MM, inclusive=(False, True)),
+    radius=1 * MM,
+    target=key_cap,
+)
+
+# Hollow out the key by subtracting a scaled version
+key_cap -= scale(key_cap, by=(0.925, 0.925, 0.85))
+
+
+# Add supporting ribs while leaving room for switch activation
+ribs = Rectangle(17.5 * MM, 0.5 * MM)
+ribs += Rectangle(0.5 * MM, 17.5 * MM)
+ribs += Circle(radius=5.51 * MM / 2)
+
+# Extrude the mount and ribs to the key cap underside
+key_cap += extrude(Pos(0, 0, 4 * MM) * ribs, until=Until.NEXT, target_object=key_cap)
+
+
+# Find the face on the bottom of the ribs to build onto
+rib_bottom = key_cap.faces().filter_by_position(Axis.Z, 4 * MM, 4 * MM)[0]
+
+# Add the switch socket
+socket = Circle(radius=5.5 * MM / 2)
+socket -= Rectangle(4.1 * MM, 1.17 * MM)
+socket -= Rectangle(1.17 * MM, 4.1 * MM)
+key_cap += extrude(Plane(rib_bottom) * socket, amount=3.5 * MM)
+
+if "show_object" in locals():
+    show_object(key_cap, name="key cap", options={"alpha": 0.7})