My version of the tower, compatible with gravitrax pro, allowing you to use walls and drop the ball in the middle.

Print instructions

• No supports needed.
• Tested with PLA/PETG
• Brim: 5mm
• Resolution: 0.2 mm
• Infill: mid-layers 60%, others 20% (https://help.prusa3d.com/article/modifiers_1767#height-range-modifier)

Note: I am in no way affiliated with Ravensburger or Gravitrax, this is just a Gravitrax compatible design that provides functionality that standard parts do not have.