Run on turbo mode (Activate this by pressing the green flag and shift) Click squares to replace them with your selected material. Press space or click the box to change your selected material.
The materials that are currently in the game are sand, water, stone, and air. There is no hold to place function because it makes too much lag. There may be a function to make your own materials soon, but it is a work in progress and might never be finished. If you want to know how I made this, it is all logic blocks. There are no if touching statements in all of the code. The screen is all clones and the code for the materials is on the backround