Unimproved Inventions >>>

[dogspoiler]

Wine

[grammafreddy]

Bars of soap, too.

and Galileo's Thermometer

[ferri]

heck. i'm stumped now. not for long. but i am. i almost said nails. but then i remembered i have a square nail driven into a knot from a tree that my grandpa gave me. lol my inheritance from him.

[dogspoiler]

Gunpowder

[grammafreddy]

Jelly powder

[grammafreddy]

Pinhole Cameras :sunshine:

[dogspoiler]

smoked food

[dogspoiler]

Chairs

[dogspoiler]

Windows

[grammafreddy]

Yardsticks

[Nibs]

Screw threads,
Wedges,
glass bottles.

[ferri]

tubes (for toothpaste, etc.)

[Air Wrench]

paddle, hammer.

I would say that paddles have been improved. Not only are they made of wood, but also fibreglass, metal alloys, and even carbon fibre composites. Also their shapes have changed with further understanding of hydrodynamics.

Hammers have changes greatly over time. Compare an early stone hammer with a claw hammer even from the 16th century, then compare that with a claw hammer specifically designed for framing today. Many changes and improvements right from synthetic rubber to make the handle more ergonomic, to the metallurgy of the head (some are made of titanium).

[Captain Awesome]

Toilet paper

(...as claimed by George Costanza)

[Air Wrench]

cloth

Nylon, Acrylic, Polyester, Carbon fiber, Spandex, Aramids (Nomex, Kevlar, Twaron), and Spectra are all synthetic fibers used to make modern “cloth”.