There is only one island in the beginning of Floating Island Story. As the game progresses and land is purchased, the number of islands becomes more and more. The terrain of each island is different. There is a sea in the middle of some islands, which affects the placement of buildings. Here is how to fill the sea.
Enter the game, click on the menu-Equipment-Skills;
Click on the mechanical skill points in the order shown below to unlock the petal compressor;
After unlocking, use flowers, steel, and bricks to make a petal compressor;
Create fill land with sand and poop at the petal compressor;
The filled land will automatically appear in the toolbar below. Select the filled land and place it where you need to fill the sea;
Click to fill the sea.