I found a nice cheap USB Mini Fan that is very useful for increasing the air circulation for indoor plants. This is especially important for promoting strong stems in young seedlings (see usage example in photo below).
This fan (Deltaco model "FAN-1") has many attractive properties, of which the four most important ones are conveniently printed on the box:
Mini — Soft — Natural — Comfortable
The fan blades are actually soft, the centrifugal force gives them tension while they are spinning. The airflow does not seem to spray any toxic or radioactive artificial materials on the target, so in that sense the fan is natural. And by the look of the thriving plants they seem much more comfortable than if the airflow had been produced for example by the storm "Gudrun" instead.
The only negative aspect of this fan is that it is a bit noisy — I don't think I would want to have one on my desk. But the plants don't mind. It is well established that plants don't consider sounds to exist at all unless there is a philosopher present who is listening.
