Steve Caplin tells Simon Rose of the latest tech innovations. A startup has worked out how to use data processing centres to heat swimming pools which cool the PCs in return. Bing's latest GPT upgrade has many improvements, but still hallucinates and makes things up. There's a revolution in the world of paint, better protection for windswept buildings, a keyboard hand heater, spirally-constructed wind turbines and Apple moving into the world of streamed classical music.