Occasionally I invent an imaginary gadget which would solve a particular problem, and then I wish I had that gadget.

People have probably heard me talk before about the stasis fridge (time stops inside it, so it doesn't even have to be cold to stop your food going off, and also you can keep hot food in it and it'll still be hot the next day), and the force-field saucepan (generated from the handle, like a lightsaber – you don't have to wash it up, you just hold it over the bin and turn it off).

But one thing I notice is that when I invent these things, other people always seem to come up with the real killer applications for them. For example, when I described the stasis fridge to drswirly, his reaction was ‘Aha, and when you go on holiday for a week you can put the dog in it’, which clearly outdid any of my own ideas.

Just now in the office, a colleague has been playing with his new gadget, a ‘digital photo frame’. He mentioned this yesterday, and so last night I was idly wondering what one of those might be. My best idea was that it should be a static display: able to retain the same image indefinitely with no power consumption, and only requiring power to change the picture. Then you could plug it into your computer and download a picture of (say) your girlfriend to it; unplug it and stick it on your bedside table miles away from any computer; and when she leaves you six months later, just download a picture of something else instead. An end-to-end digital photography solution, without resorting to outmoded paper technology at any point.

The actual photo frame in question isn't a static display, as it turns out; it's just a small and gadgetty monitor. The static idea sounded like a more interesting gadget to me – but it took another colleague to point out the ‘real’ killer app, which is that it allows you to have multiple girlfriends who don't know about each other, and change all the photos round every day so that whichever one is visiting that night doesn't suspect! And I have a nasty feeling that that would indeed be the most profitable market for the thing…