When I was young, my father brought home two wooden marble raceways similar to this module, only larger. My grandfather had made them back in the 1930s. Making and using your bridges module brings back memories of the fun my brothers and I had. Now I enjoy it with my 5 year old grandson.
Works great! Simple module, but fun to send multiple down at once. Easy to print and assemble.
I absolutely love this module, brings a lot of joy to my kid. Keep up the good work!