This reminds me of a question during one of my PhD exams (physics): how would you communicate left and right to remote civilizations, using just text (there may

This reminds me of a question during one of my PhD exams (physics): how would you communicate left and right to remote civilizations, using just text (there may have been other limitations). The idea was to use the Wu experiment [1] and the lack of conservation of parity (= there is a difference between left and right, and you can explain which is which) but was a bit taken aback by the question. Interestingly the first thing that popped in my mind was the peptide torsion direction (one of them is preferred in terrestrial life) and I started to wonder about alien abductions etc., and I fortunately got back on track with down-to-earth physics (thanks Ms Wu!) [1] https://en.wikipedia.org/wiki/Wu_experiment https://en.wikipedia.org/wiki/Wu_experiment