fai chun
Fai chun is a traditional decoration that is frequently used during Chinese New Year. People put fai chun in the doorways to create a jubilant festive atmosphere since the phrases written on it means good luck and prosperity. Customarily, fai chun is written by hand but owing to convenience, printed versions are mass-produced nowadays. fai chun is in either square or rectangular shape. It can be hung vertically or horizontally. Not only does it exist in Greater China but also in Korea, Japan, and Vietnam.
"That square thing you see posted on peoples door"