An excellent series of nine films taking you into the fourth dimension is now freely available online and cheaply available on DVD. Using superb graphics and clear, concise, no-frills presentation, the series starts with a very basic introduction to projections, then steps from two dimensions up into three and then four, and ends up with some quite sophisticated - and very pretty - geometric objects and concepts. Everyone, from complete novice to university students, will find something interesting in this series, and at 13 minutes length each, the films are a great resource for the class room. The website contains detailed background info on each episode. Go have a look, it's well worth it!