This reminded me that when I try to imagine things while almost sleeping the imagination will be actively sabotaged unless I focus very hard to wressle back control.
If I'm thinking of a plane flying it will spin out of control, if I'm thinking of sheep jumping over a fence they will stop moving or the fence will fall over.
I always wondered why people would suggest "counting sheep" as it seemed like something that'd keep me awake rather than feel sleepy. I seem to have some form of aphantasia as I can only conjure up very disjointed and foggy images with no real details.
So imagining not only one sheep but a number of sheep on a field jumping over a fence is something I can only just barely approximate with such considerable mental effort that it even makes me feel slightly anxious. This seems entirely unlike what the exercise apparently is meant to accomplish.
If I'm thinking of a plane flying it will spin out of control, if I'm thinking of sheep jumping over a fence they will stop moving or the fence will fall over.