For the 3D Design, I used Fusion360. I also tried FreeCAD in the past, but I decided to use Fusion360 as I find it easier to use. So, I tried to make only one part of the arm. The steps I followed to do this are:
So, the end result looks like this:
For the creation of the 2D Design I used Draftsight. What I created for my 2D Design was a small design of a grandpa. It does not look so realistic but I tried my best considering my poor design skills.
For the head design of the grandpa, I used the ellipse for the shape of the face and the eyes, the spline for the smile and the shape of the beard and the arc and spline to create the eyebrows.
For the body design, I used the polyline for the main body shape, the line for the feet, the rectangle and the polyline for the tie and lastly the arc and mirror for the hands. The first part of the tie is made with the rectangle. In order to change the orientation of it, I double-clicked on it and moved the corners with the mouse.
Finally, my grandpa design looks like this: