Ok, it was easy. Wasn't it? It may not have been, in fact, because I have been looking at signs like these for decades and never worked it out. But here we go.
SPOILER ALERT - read previous post first!
They are all instantly-recognisable symbols of common objects, and yet each of them represents something which is 50 years out of date, which many people will not have seen outside a museum.
Take the bike - I thought "Hey, that looks just like the Bonnie!" Actually, with that sloping-forward cylinder block it's like it's had a Yamaha Genesis motor transplant, but whatever. That style of bike (upright, exposed engine, separate head and tail lights, twin shocks) hasn't been mainstream since the 1960s. There will be many people who have only seen a design like that in a museum or in tiny numbers on the road, and yet the silhouette screams "Bike!". If they showed you a silhouette of the kind of bike that is commonest on the roads (say a Honda CBR), it wouldn't be half as recognisable. In fact, I have just done a Google image search for a sports bike in silhouette, and come up with nothing. Perhaps no-one has made an image of a sports bike in silhouette because it would look like nothing. It would just be a streamlined shape. The bike symbol above, however, is recognisable because the shape shows the function - it's a design from before the days of wind tunnels and Euro-homogenisation, a time when you could tell what something was and how it worked by looking at it. Think horse and cart; think water-wheel.
What about the others? Same story, really.
1. The train is a proper choo-choo-puff, a kind of engine not seen in the UK since the 60s, apart from on 'heritage' lines in pretty landscapes. But it's a train, not a line of identical boxes bulled by another box.
2. The car falling into the dock? Well, I would guess a Morris Oxford. Last produced in 1971. A modern car? It would just look like a blob. What's that blob doing falling in the canal, Dad?
3. The bicycle is a sit-up-and-beg design - look at those handlebars. Roller-lever brakes, full chain-guard, proper metal mudguards, Sturmey-Archer gears, perhaps a hub dynamo? Only Pashley and the Dutch and Chinese make bikes like this these days. Mind you, I think it says a lot for the bicycle that it is probably the closest of any to its modern form. Once something is right, it stays right.
4. The camera is, of course, is a proper newshound's tool, a Speed Graphic or a Hasselblad, last seen in common use in the 1940s, before Pentax introduced the Asahiflex in 1952 and we all went SLR-mad. Even for a generation for whom taking pictures merely requires a suitable phone or a shiny box the size of a credit card, this image still says "Camera!"
5. The bomb makes me laugh. Did bombs ever look like this, outside of Laurel and Hardy films? I doubt it, but the form has captured the imagination, and nothing says 'bomb' like a sphere with a fizzing fuse.
6. The 'Children' sign was a cheat. The first one was withdrawn several years ago, and replaced with the one below it. But I love the older one. These kids are straight out of 'Janet and John'. She has a ponytail and a briefcase, he has a short-back-and-sides and a satchel. You can almost make out his long socks with the Scout garter tabs. And they are going to school. To have fun. See, Janet, see the dog run! They are children-as-they-used-to-be, nostalgic even in the 1960s. And note, horror of horrors, the boy is bigger than the girl, which implies seniority and looking-after and all that. The updated version has less detail in the clothing and very little in the hair, so they could be Moomintrolls for all we know. But this time the girl is bigger and leading the way, so that's all right. And, of course, there is no mention of school. They are going to express themselves in a designated play area under the supervision of a diversity outreach worker, probably.
So there you have it. We respond better to images that ought to be in a museum, than we do to things which surround us every day. Is it a dim race-memory of how things were? That's what cameras looked like to Grandad, so that's what we react to? Or is it that the images are from a time when things looked like what they were, and not either something else, or nothing at all?
Only you can tell. And if you have any more examples, please let me know. I feel a collection-mania coming on.