Our Forester has three knobs that control air direction / speed / temperature. Knobs are much better than buttons, because you can adjust them without looking. At least, that’s the ideal situation.
Here’s the setting for airflow to the footwell:

Here’s what it looks like with airflow to the cabin:

The knob has no tactile position indicator. That greenish rectangle, located in one of seven symmetric dimples that camouflage its position, is barely visible in normal light, invisible with sunglasses, and not apparent to the touch.
Well, if conspicuous is what you want, I can fix that:

Fluorescent tape will fade quickly, but it’ll last until something better comes along. Perhaps a small pointer epoxied onto the knurled surface, extending around to the indicator?