The puzzles are dynamic events that are renewed at each OOC event: Refugees’ Days, Anlor Winn, Atysmas. Outside of these periods, one can only complete existing puzzles
    Items are distributed in turn in each of the tribes, all around Atys, including Prime Roots. In each item, you can find one of sixty fragments of a picture. It's up to you to try and put it back together!
Depending on the case, the object is a shookilat egg (Refugee's Days), a pumpkin (Anlor Winn), a snowman (Atysmas) or a chest outside these events.

Game rule :

Click on the small egg that appears randomly in a tribe every half hour to get a picture fragment. The found fragments are gathered in a special personal window (shortcut ⬆E), where the image is completed as you go along with your findings.
The little egg stays in game for 20 minutes and then reappears in another tribe after ten minutes, carrying a new random fragment. You can find out when and where a little egg is in play by clicking on the "dynamic events" icon of the map.

Note^[1] :

Outside of O.O.C. events, chests give one puzzle piece from one of the unfinished puzzles, but within the limit of 14 unique pieces per week (reset on Monday at 12:00pm CET). After the 14ᵉ piece, they will be totally random and therefore possible to get duplicates.
The window includes a message indicating if the piece found is a duplicate and therefore there is no token gain and a counter indicating the number of pieces that will be unique (unless all puzzles have been completed, of course).