Big Al wrote: I wasn't criticising you, Cubster, just thanking you without sarcasm.
I know, I know, shaddap mun!
People retain information on different ways, some people learn aurally, some people orally, some people visually, some people through reading, some through doing ... There is no such thing as a perfect learning system, since each person learns differently, so it's a case of finding out which way of communicating an idea fits the recipient best. I myself do find it tough to grasp an idea if I'm just reading or hearing about it; I'm a visual learner and find illustrations most helpful.