In a toy shop you can find those trains which are build up from a set of wooden blocks. This set of STL files is representing that idea, but now with 3d printed parts and magnets to 'glue' the block together.
Actually this design was used as an example to learn the basics of Fusion360, creating basic blocks and cylinders, learning to combine parts and pieces of the tool and the positioning should be correct. Further this tool has the possibility to combine the individual designs into the end result (with or without animation), which is great to check if everything is ok. For me it works best to have a design in mind and work that out, since it is more challenging than just drawing a box.
The magnets are 5x5x5 mm. The parts are printed with 0.2mm layer height.