Create two surfaces that meet at 90 deg. along an edge.
Create three copies of the surfaces.
Using the fillet and chamfer tools create a fillet edge, chamfer edge, and variable fillet edge.
Create a block with notch and cylinder. (make sure that the cylinder is in the center of the top of the block).
Fillet the inside and outside edges of the object. Control the dimensions so the fillet command works correctly.
