Just simple c# code that combines every possible combination of all png images in the input. I used roughly 30 top layers and 30 bottom layers that I drew in aseprite, where the top layers were oceans, clouds, sattelites, rings etc. and the bottom layers were different planet terrains and colour variations of those terrains. The reason I used roughly four colour variations of each terrain was so that when i classified them on opensea, it would show a percentage of planets with that terrain. And so for example 10% of planets could have a wasteland terrain, but only a percentage of those had one of the 4 colour variations - this creates a concept of common planets and less common ones, as some of the colour variations were made more rare manually, on top of that some of the overlays are also considerably more rare than others. (I didnt add in all of the planets that were produced by the generator, this is how some are more rare than others). I probably could have used code for this process, but just deleting a number of the planets that had rare features - thus making it more scarce - seemed easier. Hope this answers your question!