Chess grandmasters can impress audiences by playing against 30 opponents or more at the same time, and winning.
It is extraordinary to see how they instantly catch up with the different situation on each table, even cajoling slower players who have yet to start a move while they have already worked their way round the rest of the room.
Of course, schools seem to expect teachers to do this every day. Lessons must be "differentiated", they are told, and take into account pupils' varying abilities. Unlike chess grandmasters, teachers do not have the challenge laid out in clear visual form on each desk. They have to store the background to each case in their heads, effectively playing blindfold.
Only one chess player has truly succeeded at playing simultaneous chess like that, and his record-breaking feat in 1960 has still not been beaten (it was Belgian-born George "Kolty" Koltanowski, who, taking a maximum of 10 seconds to complete each move, played 56 games blindfolded, winning 50 and drawing six).
To make matters even more complicated for teachers, they are now also expected to take into account pupils' differing approaches to learning. In the games world, this would be the equivalent of switching from chess to poker to ping-pong as they move between the tables.
But a major reason that differentiation often goes wrong is precisely because teachers can see it as a simultaneous contest. They regard it as something that must be done to every pupil individually, in every lesson, rather than done for the class. Or they think that they must provide different levels of teaching for each group separately. This, as teacher trainer Geoff Petty notes, can lead to disaster, with lower expectations for weaker pupils and higher expectations for stronger ones, consequently widening the gap between them.
What is needed instead are the kinds of challenges that will stretch all pupils to the maximum of their potential, even if these require extra thought to create. So pack away the individual chess sets. A new analogy is needed for differentiation. Mixed-ability volleyball, anyone?
Michael Shaw is editor of TESpro