Instagram has launched an advent calendar called “24 Grams,” encouraging users to submit photos for a festive project.

To celebrate the days leading up to Christmas, Instagram is looking for creative pictures to make up each day of its advent calendar. For example, a picture of two rain boots represent Dec. 2, while a photo of a cat tail coiled in the shape of a “9” highlights Sunday, Dec. 9. The following days are currently blank.

Here’s how to participate: Users select a date on the calendar and interpret that number with a photo. The picture must be posted to Instagram before the deadline — the site has a ticking clock at the top of the page, counting down the hours left to participate for that day. Users are encouraged to use the tag @24grams and include the hashtag — such as #Gram9 — for each day.

Source: Mashable