This wall hook, which was manufactured at least as far back as 1908, is designed to be installed without the use of tools. Though pre-drilling might make it easier, the lower hook is used for leverage to screw it into place, and the wire is of a thick enough gauge to not get bent out of whack.

It's such an elegant piece of manufacturing, made of a single length of wire rod, put through its paces on a bender, then threaded.

The original designer is impossible to track down; it seems no one ever (properly) locked up the copyright, and versions of this were produced by multiple companies in the 20th century, including the Atlas Manufacturing Co,, Dominion Wire, Gem Manufacturing, etc.

You can find vintage versions on secondhand sites…

…and, over a century later, still buy new ones at hardware stores for a few bucks.

This is what I'd call a wildly successful design: Useful, affordable, easy to install, straightforward to source and manufacture, and long-lived.