This model is not meant for printing, but to build upon (remixing) or serve as a tutorial.

Steps:

Part 1:

Draw a construction circle at the Origin. Mark A, B, C where the circle meets the Y and Z Axis as seen above. Draw the half circle at the origin between A and B.

Part 2:

Draw 2 construction lines between A-C and B-C. Draw an Arc centered at A between E-B. Do the same on B: Arc between A-D.

Part 3:

Draw an Arc centered at C between D-E: 🥚

Good job!