One feature. One simple part.
There might be multiple ways to solve this puzzle and I am always impressed with your creative solutions.
Warning! Spoilers ahead:
A simple extrusion makes this part. The "trick" to the puzzle is using a 3D sketch. Because the two profiles have the same thickness (5/8") the sketched profiles need to be separated by the same distance (I left one blue to make it clear). I've never had many practical uses for extruding a 3D sketch, but it works perfectly for this puzzle.
Image below showing the 3D sketch profiles, and extrusion feature. Thickness of the extrusion is reduced to better show how both profiles will extrude equally.