In 1923 Kandinsky proposed a universal correspondence between the three elementary shapes and the three primary colors: the dynamic triangle is inherently yellow, the static square is intrinsically red, and the serene circle is naturally blue.
The series ▲■● represents Kandinsky’s attempt to prove a universal correlation between color and geometry; it has become one of the most famous icons of the Bauhaus. Kandinsky conceived of these colors and shapes as a series of oppositions: yellow and blue represent the extremes of hot/cold, light/dark, and active/passive, while red is the intermediary between them. The triangle, square, and circle are graphic equivalents of the same polarities.
In March 2021, I went through a fun self-imposed experiment: no emoji for 2 weeks. Not on social media, not in private messages, not even as Slack or Discord reactions. No emoticon either: the goal was to communicate without illustrations, only with words. I did a semi-rigorous (a.k.a. half-assed) diary study, taking notes on my feelings and behaviour.
A meta note, inspired both by Proust and by this book about Proust: after reading a book, when you're making notes, don't refer to the book; just write down the most interesting things that come to mind. This is a better way of digging out what actually struck you about the book; as soon as you have the book to reference, you will start looking up the bits you "should" write about, and end up aiming at comprehensiveness rather than interestingness. Your actual criterion should be whatever interested you. Later, you can fill in quotations & references.