Randall Munroe came up with an elaborate interactive comic for April Fool’s Day, but due to technical difficulties, couldn’t get it online until Sunday night. Called Garden, it’s a game of sorts, but requires patience. The hover text says, “relax.” You are given what I first thought were UFOs, but they are adjustable grow lights. Set up to three grow lights and leave your garden to grow. According to the site Explain xkcd,
If you leave the lights on and wait (or relax) then the plants in your garden start to grow slowly. The plants appear one at a time slowly, but only a few of them actually grow. There is a large tree that does, but most other plants just appear. Some of the plants sway in the breeze.
Also animals and characters including Megan, Ponytail and Cueball may appear. See examples here 1663: Garden/Images.
Every so often the image will refresh. You can change the number of lights, their position, direction, beam width and the color temperature from red to yellow to white to blue. How much this affects the growth is hard to say, but there seems to be some correlation.
They have tips there to help you out. As your garden grows, the URL will change. You can copy the URL at any point to share and show people how your garden looks, and they won’t be able to change it. What you see above is my garden from a few minutes ago. Who knows what will happen if I manage to leave that tab open for the rest of the day!