I have designed and printed a collection of add-ons and spare parts for the Hape marble run Quadrilla. Have fun with it!
This is a standard tower to be able to build bigger and more complex marble runs. It has a sideways passage from the top and at the bottom an entrance guiding the marble downwards.
Edit 25.01.2018: I did some minimal changes to the bottom hole diameter and position, because I realised, that on some wooden tracks the marbles could get stuck. In addition I added two other kinds of towers.
Edit 15.02.2018: Added a new tower (#4) which is not included in the original set. Marbles from the top and from one side, both can go down through one hole.
Print it with the bottom ring looking upwards.
Can be printed without support but a little break away support makes the side-way inlets and the flat ring on the upper inside look better and need less post-processing.