iiinova — where your digital self keeps evolving

Replies

By Cory Doctorow (GPG 0xBF3D9110957E5F4C) @doctorow.pluralistic.net · 05/03/2026

There are lots of intersections that are dangerous for cyclists, but what made Ipsley Cross so lethal was a kind of eldritch geometry that let cyclist and driver see each other a *long* time before the collision, while providing the illusion that they were *not* going to collide, until they did. 3

pluralistic.net

Pluralist: 19 Feb 2020 – Pluralistic: Daily links from Cory Doctorow

162

By Cory Doctorow (GPG 0xBF3D9110957E5F4C) @doctorow.pluralistic.net · 05/03/2026

This intersection is an illustration of a phenomenon called "constant bearing, decreasing range," which (the article notes) is well understood by sailors as a reason that ships collide. I'm not going to get into the trigonometry here (the Singletrack article does a great job of laying it out). 4/

pluralistic.net

Pluralist: 19 Feb 2020 – Pluralistic: Daily links from Cory Doctorow

250

By Cory Doctorow (GPG 0xBF3D9110957E5F4C) @doctorow.pluralistic.net · 05/03/2026

I am, however, going to use this as a metaphor: there is a kind of collision that is almost always fatal because its severity isn't apparent until it is too late to avert the crash. Anyone who's been filled with existential horror at the looming climate emergency can certainly relate. 5/

pluralistic.net

Pluralist: 19 Feb 2020 – Pluralistic: Daily links from Cory Doctorow

160

Juris Canis @x-tweeter.bsky.social · 05/03/2026

www.boatus.org/study-guide/... This is a crazy but sneaky-common phenomenon on the water. Here's a great photo sequence from BoatU.S. illustrating the view from the helm in this situation and how easy it is to think you'll clear that other boat until nope. If that reticle hasn't moved, you should.

Screenshot from BoatU.S. navigation rules study guide webpage that reads:
Potential Collision Situation
When the distance between two vessels decreases and the relative angle of the other vessel of the bow remains the same, then you will soon be trying to occupy the same spot in the water - a collision situation. Change course or reduce speed, even if you are the stand-on vessel.

Under the text are three photos. Each shows a compass bearing of 10 degrees and the view through a scope with a vertical reticle. A container vessel is seen in at a distance in the first photo and progressively closer distances in the second and third. The vertical reticle intersects essentially the same spot of the container vessel in all three photos.

000