Friday links

Paraskavedekatriaphobia: Why is Friday the 13th Considered Unlucky?

The Physics of the Star Wars Trailer’s TIE Fighter Formation.

The Unlikely Struggle Of The Family Whose Neighbor Is Area 51.

Advice on hair washing from the 12th and 17th centuries.

World's fastest lawnmower reaches 133 mph.

I'm not sure why they don't still do this: in the early 1950s, as part of a "cost conscious" program, the U.S. Army put price tags on equipment.

ICYMI, Wednesday's links are here, and include Veterans/Armistice/Remembrance Day links, the science of how female turkeys choose mates (and avoid the ones they don't want), and a set of characters from classical paintings inserted into contemporary settings.