Things seem to be settling down at 2lmc, the house I live in. We have a more-or-less functional living room AV setup, with a Dreamcast for Rez, basically; we've got lots of bookshelves, so I can reduce the boxiness of my life, and we've put up the art that we brought with us.
That made me think, since my room has nothing on the walls (just like all of my bedrooms since I've stopped being a student, really), and I thought it might finally be time to change that. Something else that lurked in my brain was the site someone posted to scribot some time ago which had aerial photos of all of London, and of course Microserfs, which has been a favourite book of mine for a while. The obvious crossover point? Huge blown up photocopies of London's cloverleaf junctions.
Starting at the link provided for the junction between the M25 and M1, I at first followed the navigation provided, first clockwise, to the M25/M11 interchange, and then back to the strange but somehow lovely M25/M40 junction, before wondering about what other stuff there was about cloverleafs on the web, and how to explain what they are.
The explanation is fairly simple. Most (British) motorway junctions have access ramps to a roundabout, which is fine if you're joining a small road, but the last thing you want to do to a full motorway is have every car slowing to 20 mph just to get under one motorway (and anyway, which one do you slow down?). So there's a whole class of interchanges to enable both motorways to continue onwards without interruption and for cars to change between them as quickly as possible. I thought these were all cloverleaf junctions, but the British Interchange Directory and the Kurami guide both put me right; most of the M25 interchanges I love are either four or three level stack junctions.
Thus corrected, I carried on anticlockwise about the M25, which was pretty much designed deliberately to join up the motorways radiating from London, and hence is home to many of the bigger junctions in the UK, in particular the M25/M4 stack. There's also the M25/M3 interchange, and the also impressive M25/M23 junction, which like that for the M4, carries a disproportionate amount of traffic, as it's near a major airport.
Although there are other major junctions on the M25 (the A1M, the M25/M26 and M25/M2 in particular) none are quite as impressive, and there are very few outside London; the M4/M5 springs to mind, though.
There are a few sites with American interchanges, which, because they have the land (and the money) to play with, tend to be bigger, more symmetrical, and somehow less interesting. The contortions the M40/M25 junction goes through are quite interesting, and you can see that some of these interchanges have been squeaked in around houses and other existing features.
Of course, despite getting all these URLs and making a biggish blog post out of them, I still haven't actually printed out or blown up the photos. Ah well, there's time for that later. And my art took two years to make it back to walls; there's no rush...