Cardboard connectors for marble tracks

Hello thingies,

In the corona period, i build a lot of marbletracks with my son of 8.
We used old cardboard boxes to make the tracks and connected them all together using lots of ductape.

I then thought that it must be possible to make it easier and i started to design connectors for cardboard tracks using fusion 360.
Now a few weeks in designing , 3d printing ,redesign , tweaking and new printing ,i came up with some parts.

I also thougth how can i make pilars for the tracks to get some hight? , therefore i thought of using lego bricks, so i added a lego plate to the connectors.

Hope u will print my cardboard marble track connectors and have fun with it .
All suggestions are welcome

All my great thanks go out to FredGenius , my support and refuge designing things !!
https://www.thingiverse.com/search?q=fredgenius&page=1