>>512267800 (OP)There are hollow ones for tires. An important point of note is a tiny port for escaping air.
https://m.youtube.com/shorts/ioNGCqldPbs
Here's a place to purchase some or catch ideas to make them. I advise against it, as in similar fashion to landmines, youโll never be able to get all of them back up, and invariably itโll just end up hurting some random innocent. A child or a dog. Somebodyโs horse.
Still, freedom. And itโs one of the greatest, oldest, ridiculously efficient area denial weapons. I saw one guy selling them waaay overpriced who just tack-welded wire nails together and clipped / filed down the ends.
https://freedomgear.org/product/ultimate-razor-sharp-ground-spikes-caltrops/
Live wisely. Make good choices.