I imagined a desert with sand dunes, so I couldn't see how large the desert was, but the cube was a size that could easily be held. It was black and a few meters away from me, a bit further down the side of the dune. I think it was made from something non-natural. Like plastic but not plastic, idk I don't know much about materials ig. It felt sturdy.
The ladder was wooden brown, lying one or two meters down from the cube. It looked like it had slid down fairly recently. I just wondered what a ladder was doing in the desert, away from everything it could be used for.
The horse felt like it was in its natural habitat, like it belonged there. It stood between the cube and the ladder, but a little closer to me. Its rear was closest to the cube, but it turned its head to sniff in the direction of the cube. Then the horse jogged up to me. Brown fur and manes, playfully darting around the area, but never going far. No saddle, no reins, free to go wherever it wanted.
The storm was a dark cloud, far away. It was a large storm, and even if it were to decide to come my direction it would dissipate before it got there. I don't think it was moving though. (when I got to this part of the exercise there actually was a sound outside that could be mistaken for thunder XD)
The flowers sprouted at the lowest point between the dunes, along with some grass. Some lone flowers found their way up the dune the ladder and cube (and me) were on. The horse got all giddy, lifting its legs high while walking in place, then headed over to the patch of grass and flowers and rolled in it. The flowers made it feel like this was no longer a desert. They were white and a light yellow, too many to count.