Ahaha, nice guess but not quite! They are frames of mind- they are part of the weather system of the ‘stuff of thought’ in the world. When they get a bit more filled in they can level out and form platforms (or, rather, solid thoughts), which as we’ve seen can align (solid thought patterns), and be traversed to progress. The frames of mind which collided with the ground in Suture/Negative did so because they were over the Plains of Hesitation, and while most of them are fleeting anyway hesitation can bring one crashing down and evaporate it in moments. To put it simply they are a form of cloud, but not quite?
Don’t think about it too much there is a certain level of nonsense to the whole thing :’D