This rendering was done in Blender. Originally, I was inspired by the images from Nicolas K Feldmeyer in his "AFTERALL" series, which you can find here: → http://www.feldmeyer.ch/index.php?page=291
So I started out with some generic shapes on a blank mountainous landscape. I was able to make a replica of Feldmeyer's image, but at this point it was really more of a copy and nothing "unique". I learned that often the most minimal ideas, executed well, have their own merit.
Then I remembered a cool → Instagram account by Josh Pierce, whose images have the same basic structure - glowing shapes in the sky and landscape in the foreground.
So I took this idea and also added some Blender fog. Using fog volumetrics in Blender Cycles is usually very heavy on render times, so the final image eventually took about 2.5h to render at 600 samples and 2400 x 2400 pixels.
At this point, I had swapped the white square for a colorful glowing frame... and still something was missing. Something to take the visual interest. In Feldmeyer's images, the visual interest is coming from the shadows and shapes created by the white square. For Josh Pierce, it's the colorful and surreal landscapes.
To add visual focus, I added a tree and to increase the surrealism, I gave the trees glowing leaves. This took some tinkering around in the leaf material in cycles. A very colorful red HDR image in the background nicely filly the sky.
Then I rendered it out and gave it some crunch in Photoshop for the final image.
And to push the idea even further, here it is mounted as the center for some album artwork by a fictional band. Would look great on Vinyl!