1: Beautiful long translucent net curtain, stretching for the whole of the border. It wafts in the soft Irish Air, allowing free-ish access both ways. Possibly a neutral light cream colour, but it must be machine washable!
2: Schroedinger’s border. Philosophy students patrol this there-yet-not-there border, explaining to hardened lorry drivers who barely speak English how the principles of quantum physics could apply to this knotty European problem.
3: Nostalgic. Watch towers with glowering men who look a bit like Liam Neeson with machine guns and Kevlar vests, heavily armoured Land Rovers bristling with aerials, and dreadful murals any self respecting art teacher would only award a ‘D’ minus to. DMZs between towers to allow paramilitaries of both sides to play games of football against one another, say on Christmas Day and July 12th.
4: Fictionless borders. Under a proposed law only works of fiction would be subject to tariffs. Non-fiction would be unaffected unless written by Boris Johnson, as would self-help books about indecision.
5: Border terrier – just throw him a scrap of food and he’ll wave you through the checkpoint then bark as you disappear into the distance.
6: Religious border. People stop at N/S line and argue about whether transubstantiation is genuinely the actual consumption of the blood and body of Christ, and whether a whim of Henry Vlll so he could marry some woman is the basis of all British history, you bastard.
7: A thick trail of butter. This would attract cats and other animals along the border who would just lick it all day and nobody would want to run them over. Whether the butter would be made with a EU subsidy is still a sticking point which will need ironing out.
8: Hi tech solution. Banks of cameras and computers would identify customs documents, read number plates identify faces and telepathically understand why you wanted to go to Northern Ireland in the first place and automatically charge your Amazon account accordingly.
9. Herbaceous border perhaps with a shrubbery and a little path. Pretty!
10. Boarding house borders. Flat capped men sharing rooms to rent in small run down houses along the divide, run by kind-hearted landladies of a certain age. As seen in old films on ITV OAP. Baths 10d extra and no visitors in the rooms after 6pm, if you please! This is a respectable establishment. And no arguing about that Common Market thing!
hat-tips to Oxbridge, riesler, sinnick