The 3×3 layout shows up everywhere: (1) the calligraphy practice grid, (2) sudoku and tic-tac-toe, (3) Chongqing
九宫格火锅 — a hotpot pot divided into nine compartments so different broths and ingredients don't mix, (4) the standard nine-photo grid on WeChat Moments (
朋友圈 péngyouquān) and Instagram, often planned visually before posting.