I built was a air pollution no more machine and what it did was suck bad air into the machine and then keep it in a container then you could empty it out into a bag that came with it.
The reason I chose this is because today the is to much air pollution which can also lead to lung cancer which can lead to a stroke or death.
1. probably finding all the right pieces and making them go together
2.I learned that making stuff is not easy and its hard to make stuff work when you want them to
3.I'd say make every single second count that you have working and making and also be concentrated