HILLARY CLINTON said it was hard to imagine there had been yet another school shooting. Seven such incidents have occurred in the States over the past 18 months, and they will continue happening, probably with increasing frequency, until the underlying causes are effectively addressed.

The reasons for such violence are uncontentious and well-known. But just because the problem is understood and has a solution in theory does not mean that it will be solved in practice. Social factors, values and personal interests - in short, political considerations - get in the way. With a powerful gun lobby, controlling a gun culture that allows easy access to lethal weapons to anyone unable to control their anger, turns out to be a hot potato too far.

Solving a social problem is of a higher order of complexity than an intellectual problem considered in isolation. People are involved. Like a good puzzle, such a problem must be anti-intuitive, which militates against the very consensus necessary to motivate change in a democracy.

Great minds do not think alike. Otherwise they wouldn't be great. Societies, crowds and groups have their own logic. You can reason with individuals. But demagogues don't reason with crowds - they sway them. Even if all agree on what needs doing - power, skill and political will are needed to effect change. But we elect politicians not for their problem-solving skills, but on image: how they talk and move. The line from the Tom Lehrer song: "At last we have a senator who can really sing and dance!" points up a truth. So expert advisers are needed.

But what if social good and personal self-interest conflict? You can always fall back on Maslanka's Third law: "For every expert advising a course of action, there is one who advises the exact opposite." Choose the right experts and you can free yourself of doing the right thing.

Solutions to last week's problems

1 It is tempting to "see" the shortest route between opposite diagonals of the cube as shown in Fig 1a. Unfolding it does not distort the surface, however, and the shortest route is as in Fig 1b. 2 See next week's Puzzlemaster.


Points to ponder

1 Three flies swim in a straight line away from a common starting point in a bowl of soup. How can the starting point be found? (Fig 2)

2 3 legs good, 4 legs not so good. Under what wobbly circumstances? Why?

3 Find a single-word anagram of COSY IGLOO.

Comments to: indy@ puzzlemaster.co.uk