I make these wall calendars every year with one big image in the background or twelve themed images in alternating squares.
I note the birthdays of friends and relatives (and cats) with their name on the date plus a bright gold star behind it. (To protect privacy I’ve changed them all to “Name” here, but you get the idea.)
The 2025 image is of a color wheel created by Martha Bernstein, a German color theorist of the early 20th century.
[This is a] hand-colored color wheel from another forgotten color theorist, Martha Bernstein! Her book, “Die Schönheit der Farbe in der Kunst und im Taglichen Leben” (The beauty of color in art and everyday life, 1921) collected her lectures on color theory mainly from before WWI. She continued as a color theory educator at least through the 1920s, and the revised second edition of her book was even translated to English in 1928.
—art.pete.repeat
https://www.bbc.com/culture/article/20220401-the-women-who-redefined-colour