Furoshiki - Carrying stuff with a square of nylon or silk cloth

The cloth material appears to matter because it affects the strength of the knot, as well as ease of disassembling the knot.

A brief video showing some basic techniques

A web page showing more techniques

The wine bottle technique is pretty cool, if only because it is vastly better than the token paper bag approach used currently by grocery stores. A square of silk or nylon cloth is more packable than a single-purpose reusable shopping bag, you can tie it so it has handles, and if something spills or breaks, the cloth is washable.

This is the type of low-tech, low-cost, high-effectiveness solution that I like.