Opening a window is not enough for many situations such as a classroom with 30+ children. What you can do is make a relatively cheap filtration device - https://www.youtube.com/watch?v=YI74VO1n1S0

Home made air filtration devices can be made cheaply - https://www.youtube.com/watch?v=YI74VO1n1S0

We need to set the engineers loose to ensure clean air for all public indoor spaces. This can be done through a combination of ventilation and filtration.

Cholera was stopped by cleaning the water we drink, We can stop Covid by cleaning the air we breathe.

Michael Caine: 'I voted Brexit. It was about freedom, not immigrants'. Truth is the people of the UK voted to be governed by our own elected representatives in London, not unelected bureaucrats in Brussels. The remainers don't like this because of their own vested interests - eg villa in Tuscany, ability to work in the EU etc.

If Smalltalk is written in a pure OO style with many very short methods, then it can be a nightmare to read. This is because it's very difficult to see the "big" picture when all you have are many classes with lots of methods each of which tells you very little about the overall flow of the program.