spatial relations and tidbits

Today I learned that when you are making the door in the front piece of the nylon dome tent you're making, you shouldn't make your seam allowances too big when you sew in the zipper, or the door frame will be too big and your door will be too small.

Also, apparently there are some secret shopper jobs that aren't scams, and cornstarch has a particle size of 0.1 to 0.8 μm.

I was going to leave it at that, but on the topic of digital drugs:

For binaural beats to work, you must use headphones. Different sounds are played in each ear. The sounds combine in your brain to create a new frequency. This frequency corresponds to brain wave frequencies.

There are different brain wave frequencies. These frequencies are related to different states like relaxation and alertness.

Digital drugs supposedly synchronize your brain waves with the sound. Hence, they allegedly alter your mental state.

I think it's very enterprising of young people to have figured out the mechanism behind that machine on Star Trek that made people crazy and the 'brown noise.' I'm impressed.