The word "Easter Egg" originally comes from the belief that in Christianity, Easter rabbits hide baskets containing eggs in their homes on the eve of Easter. Currently, it refers to a message or function hidden in a program developed by a game or program developer. East Egg is a feature that can be found or not, and is often found in unexpected places. There are times when things that have always been the same in daily life seem different, and there are times when things that are invisible are seen. The singularity found through the cracks in the world moving according to its own order is "Easter Egg," and I would like to explore and express these East Eggs in puzzles.