Frequent coffee drinkers are all too aware of the scourge of coffee rings and as such, are careful about where they place a mug, lest they drench a memo or report. But when coffee stains aren't ruining important documents or staining greeting cards, they're admittedly kind of pretty. In the past, artists have even decided to take advantage of the watercolor-like gradient they produce.
Singaporean artists Jenn Perng and Ink Julep put their heads together to create imaginative postcards that utilize the unique look of a coffee ring. Each postcard features an unfinished illustration that becomes complete when the recipient places their cup on top. The drawings all require a round shape and range from a panda to the planet Earth.
The series, called PostCups, is available on Big Cartel. The set comes with seven whimsical postcards. The only thing left to do is figure out which of your highly-caffeinated friends to send them to.