This is a wonderful film. No fancy sound effects. No banal voiceover. Every word has a place here, and formatting is of such little concern that words are allowed to split across lines in awkward ways.

Clearly, the focus was on the graphics. And, oh, how lovely these animations are, how clearly they convey the message.

There was a time when educational films were based on two expectations that seem foreign and perhaps quaint in today's click-driven world. First, that the viewer already has some background knowledge, usually gained by staring at textbooks late at night, doing assignments without a safety net provided by, well, the 'net. And, second, that the viewer fully expects that the film will provide clarity on some issues that might be hard to grasp well by making marks on paper.

This reminds me of the days when educational films focussed on educating, not amusing. What a breath of fresh air this is. Fresh air from a dusty past.