Magnetic connectors and coupled track segments for rolling balls down a vertical surface

A method comprising:

• three-dimensionally (3D) printing a first connector that is attachable to a first end of a track segment, the track segment including a channel for holding a rolling object, wherein the first connector is a single piece that is slidable onto the first end of the track segment;
• pausing the 3D printing of the first connector part-way through the 3D printing of the first connector;
• inserting a first magnet into the first connector while the 3D printing is paused, the first magnet to enable the first connector to be attachable to a ferromagnetic surface;
• three-dimensionally (3D) printing a second connector that is attachable to a second end of the track segment, wherein the second connector is a single piece that is slidable onto the second end of the track segment;
• pausing the 3D printing of the second connector part-way through the 3D printing of the second connector;
• and
• inserting a second magnet into the second connector while the 3D printing is paused, the second magnet to enable the second connector to be attachable to the ferromagnetic surface.

An assembly comprising:

• a track segment including a channel for holding a rolling object, the channel comprising two sidewalls and a middle wall, wherein a bottom surface of the middle wall comprises a lock depression;
• and
• a 3D-printed connector comprising:
• an interior with a locking surface and two sidewalls that extend from the locking surface, the locking surface comprising a lock protrusion that fits within the lock depression of the middle wall of the track segment;
• and
• a front face formed at an end of the two sidewalls and the locking surface, wherein the front face comprises a female registry feature shaped to receive a male registry feature of another of the 3D-printed connector.