What is this thing?

5412 readers

1 users here now

Let us help you identify that mysterious object you’ve found.

Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.

founded 1 year ago

MODERATORS

mykl@lemmy.world

162

[Solved] Anyone know what this is? They are embedded in the sidewalks around the city (programming.dev)

submitted 1 week ago* (last edited 1 week ago) by catch22@programming.dev to c/whatisthisthing@lemmy.world

38 comments fedilink hide all child comments

Any ideas?

you are viewing a single comment's thread
view the rest of the comments

[–] KreekyBonez@lemm.ee 2 points 1 week ago

once you start to notice them, you'll never stop seeing them everywhere.

this one is a magnetic nail, so it can be found more easily with a metal detector, which is pretty handy when there's a foot or two of snow on the ground.

you'll also see crosses, squares, and triangles carved out in stone, as well as the super common drill holes in concrete, which are typically only for temporary points.

I've found 100+ year old control points drilled into old stone walls, and they can still check within like ¼" of the new maps.