The penis mightier than the sword

This source says cats can’t see them.

https://www.sciencealert.com/humans-actually-have-secret-stripes-and-other-strange-markings

I have no idea if sciencealert.com is reliable.

These are the Things that Make a Man

Iron enough to make a nail,
Lime enough to paint a wall,
Water enough to drown a dog,
Sulphur enough to stop the fleas,
Potash enough to wash a shirt,
Gold enough to buy a bean,
Silver enough to coat a pin,
Lead enough to ballast a bird,
Phosphor enough to light the town,
Poison enough to kill a cow,

Strength enough to build a home,
Time enough to hold a child,
Love enough to break a heart.

Terry Pratchett, Wintersmith

In a ML system, how does labor aquire the tools and facilities they need to do their work? If they pay for it themselves do workers who join later need to compensate the earlier workers?

If bank loans still exist and the workers take one, they are giving some of the value they create to the bank. Again, do future workers compensate past workers who made that sacrifice?