It takes a lot of water and wood to produce one sheet of paper. We often use less than 5 minutes of paper produced at high environmental cost. However, a circular card can be used for many years. It’s especially cool when the card comes back to you in a circle at some point. The idea is that you make a double-sided card. You write your greetings on an extra sheet and send it to a friend. The following year, your friend exchanges the extra sheet and sends the whole card back to you or your friend! And that’s how the card circulates, and how many banknotes of water and wood are saved!
