It would be a christmas gift if someone teached me how to create the arm. Thanks for your attention
This task is quite simple.
- Add the torus.
- Go to edit mode and cut the half of it (actually more than a half) in "face mode".
- Flatten this figure a bit.
- Use a preset viewpoint (any dot of navigation "cube" that lets you to see the figure at a whole).
- Enable "Snap - Increment", choose tick strict snap to grid, and snap the figure to grid. Add three separate dots (left/right mouse button + Click). Snap them to grid too!
- Select all (A button) and use Bisect. Connect dots to slice the figure.
- Select everything that you don't need and delete. Disable snap.
- "Extrude along normals" this figure.
- Voila! Then you can add other inner parts that are simpler.