Chun lian is a special type of Duilian, or couplet. It is used only during the Chinese New Year as part of its celebration. While duilian is permanent, chunlian is a temporary decoration to be placed on the entrance of the house, somewhat akin to Halloween and Christmas decorations.
Duilian comprises of a couplet written on vertical strips of red paper in the best calligraphic style one can muster.
The first (called upper) line is posted on the right side of the front door.The second (called lower) line is posted on the left side of the front door.
In addition, a third horizontal piece may be posted across and on top the door.
The above are known as "duilian which are placed at the side of the doors.
The above are chun lian and the more commerical ones comes with cute pictures.