I've never done any patent work anywhere but the US. Can't say what copyright law would be like elsewhere. I know that european patent law is significantly different from US, or at least it used to be. Last I heard the US was being brought to the more usual standard. The issue had to do with "first to file" versus "first to invent".
Wait... so our speedcubes are in fact illegal? Really?
From what I've seen they are.
I think there's a very good reason why Seven Towns doesn't push it. In fact I'm a little surprised that they bother with packages with one or two cubes at the border to a retail customer. If I were them I'd only bother with mass shipments to businesses.
If they made a stink about it at the world cubing contest, for example, the whole story would get traction world-wide.
The inevitable result would be that millions of people would learn that there are other cube makers than Rubik and that there were ways to buy them. Dayan would start selling off-color cubes to US stores. It could end up cutting into Seven Towns' control of US retail market.
As it is, they risk having the story get out every time they mess around with an end user. I can't imagine why they'd do that. The risk / reward is incredibly negative. The last thing they want is for Walmart to be selling a Dayan non-Rubiks cube.
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One of the things I'd like to do is to make up a few million speed cube advertising stickers. They would give the names of the world's best speed cubes and tell the reader to buy them on the internet. We pass them out at each cubing contest for free. When you get back home, you drop by Walmart and add these stickers to all their Rubiks cubes. Uh, of course I'm kidding, this would get us in trouble, the point is that getting reporters to talk about the fact that speed cubers don't use Rubiks cubes would be roughly equivalent to going into Walmart and putting a sticker on each Rubiks cube saying "you're a loser if you buy this cube."
The thing I find really annoying about this is that the usual reason for claiming that copyright law is in the interests of consumers (it's not, it's in the interest of copyright holders, obviously) is that it protects consumers from cheap knock-offs. But in this case, the copyright violators make a product which is far superior. So I don't think that Seven Towns would win in the court of public opinion on this. I just can't imagine why they would push it. It could be a big disaster for them.