Another simple idea for the future. Variable grip under electronic control.
Shape changing materials are springing up regularly now. There are shape memory metal alloys, proteins, polymer gel muscle fibers and even string (changes shape when it gets wet or dries again). It occurred to me that if you make a triangle out of carbon fibre or indeed anything hard, with a polymer gel base, and pull the base together, either the base moves down or the tip will move up. If tiny components this shape are embedded throughout a 3D structure such as a tire (tyre is the English spelling, the rest of this text just uses tire because most of the blog readers are Americans), then tiny spikes could be made to poke through the surface by contracting the polymer gel that forms the base. All you have to do is apply an electric field across it, and that makes the tire surface just another part of the car electronics along with the engine management system and suspension.
Tires that can vary their grip and wear according to road surface conditions might be attractive, especially in car racing, but also on the street. Emergency braking improvement would save lives, as would reduce skidding in rain or ice, and allowing the components to retract when not in use would greatly reduce their rate of wear. In racing, grip could be optimized for cornering and braking and wear could be optimized for the straights.
Although I haven’t bothered yet to draw pretty pictures to illustrate, clothes could use variable grip too. Shoes and gloves would both benefit. Since both can have easy contact with skin (shoes can use socks as a relay), the active components could pick up electrical signals associated with muscle control or even thinking. Even stress is detectable via skin resistance measurement. Having gloves or shoes that change grip just by you thinking it would be like a cat with claws that push out when it wants to climb a fence or attack something. You could even be a micro-scale version of Wolverine. Climbers might want to vary the grip for different kinds of rock, extruding different spikes for different conditions.
Other clothes could use different materials for the components and still use the same basic techniques to push them out, creating a wide variety of electronically controllable fabric textures. Anything from smooth and shiny through to soft and fluffy could be made with a single adaptable fabric garment. Shoes, hosiery, underwear and outerwear can all benefit. Fun!