Sorry if this topic has already been made or all of you know about it. But oPryzeLP on YouTube made a custom flatland tool where you can customize all 128 and layers of the flatland, 128 not 4, I made and entire world out of cakes, I think it's cool because you can make the layers anything you want, For Example: You can make 1st layer (normally bedrock) sand stone or sand, 100 blocks of air, 1 block of glass then 26 layers of water and you have a Bikini Bottom Map. Here is the video he made: