The Japanese are great at inventing complex systems of rules, and not so great at explaining those rules to foreign visitors.

Compared with U.S. cities, Japanese cities bend over backward to help foreigners. The countryside is another matter.

A whole bunch of big technological shocks occurred when Asian innovations - paper, gunpowder, the stirrup, the moldboard plow and so on - came to Europe via the Silk Road.

Major power and telephone grids have long been controlled by computer networks, but now similar systems are embedded in such mundane objects as electric meters, alarm clocks, home refrigerators and thermostats, video cameras, bathroom scales, and Christmas-tree lights - all of which are, or soon will be, accessible remotely.

The embrace of a new technology by ordinary people leads inevitably to its embrace by people of malign intent.

Smartphones can relay patients' data to hospital computers in a continuous stream. Doctors can alter treatment regimens remotely, instead of making patients come in for a visit.

Scientists have established huge numbers of links between particular diseases and snippets of DNA, but in the great majority of cases, this has not yet been translated into treatments that can help cure patients. These treatments will come - tomorrow, or the day after.