|The shops are full of them.|
Here is one manufacturers page with a lot of different models.
"Advent is the beginning of the ecclesiastical year, and it also marks the start of Christmas festivities in Sweden. More people visit Swedish churches on the first Sunday of Advent than any other time of year; they come to sing the well-known Yuletide hymns. This first Sunday is also the day communities decorate their streets and squares with wreaths, garlands, lights and Christmas trees. At home, Swedes light one candle on each of the four Sundays leading up to Christmas, in special four-pronged candelabra.
Another way of counting the days until Christmas is the Advent calendar, a card with "windows" that you open, one by one, for each passing day until Christmas Eve. These calendars, which were introduced as late as the 1930s, have become increasingly popular. Swedish radio and television broadcast daily Advent programs for children based on a specially published calendar.
|During Advent many people hang luminous stars of paper, straw or perforated metal in their windows. Introduced from Germany around 1910, these stars have become a central feature of Swedish Advent celebrations."|
|Source: "Traditional Festivities in Sweden"; Author: Ingemar Liman; Published by: The Swedish Institute, ISBN 91-520-0113-X|