If you comment on this blog, and in numerous other places on the web, you are asked to "prove you are not a robot" by typing into a box the letters that you can read on the screen. These are, as I'm sure you've all seen, written usually in a squiggly type pattern, or in varying sizes and/or fonts although lately I have also seen things like sums and photos of house numbers. The logic of course is that us humans can identify these not so easy to read characters, whereas a computer/robot/spambot won't be able to. Only a month or so ago I remarked how easy they were to read, never having got one wrong. Now, in the last couple of weeks I have had to re-try incorrect entries more often than I have got them right, one actually taking five attempts. So, are these little "tests" being made harder because robots are getting cleverer, is my eyesight getting worse or, and more likely, does my monitor screen need a damn good clean?