On April 1st Reddit uploaded a 1,000 x 1,000 pixel canvas to the /r/place subreddit. The canvas was blank except for the message:
"There is an empty canvas. You may place a tile upon it, but you must wait to place another. Individually you can create something. Together you can create something more".Reddit users could select one pixel on the canvas and fill it in with any color from a 16-bit palette. That user was then locked out of the canvas for five minutes. After five minutes the user could contribute another pixel to the canvas. The five minute lock-out for individual users meant that different users obviously had to work together to create a recognizable design on the canvas.
The /r/Place Atlas is an interactive map of the complete /r/Place canvas as it looked on the day contributions were stopped a few days after April Fools Day. The map allows you to zoom in and out on the canvas. You can also hover over individual designs on the map for an explanation and links to any relevant subreddits or websites about the design. The map also contains a search facility to automatically find any of 1207 different designs on the canvas,