As Lego (the old blocks not the 'new' hi-teck stuff) are now in the public domain, can I make a game where the graphics are made out of lego blocks?
Well, I can, but is it legal?
First, I am not a lawyer, this is not legal advice, if you follow my advice and get sued and lose your house then it's your fault not mine.
Unfortunately, as simple as that question is, it really needs to be broken down into two questions.
1) If I get sued for copyright infringement, will I win?
Maybe! Assuming those pieces are in fact public domain now, then it seems like a rather clear victory. Now, for the sake of this entry, I'm going to assume you win, unquestionably. I don't know that for certain, but we're just going to make that assumption.
2) Will I get sued?
Unless you have a nice big legal war chest to rely on, getting sued is almost as bad as losing. You can't hope to match Lego's legal funds. It will not happen. You'll go to court, and you'll probably blow thousands of dollars just on prep work. And then, even if you win, there's no way you're getting that money back without a second court case - more money, and you're not even guaranteed to win that one.
You may want to read this story. For posterity, here's the important bits:
As a film student in early 2001, I was a juggernaut. I was making a lot of short films that were garnering moderate acclaim, and I was always pushing ahead, making bigger and bigger projects. For my senior thesis, I wanted to base it on a short story by Isaac Asimov, which was part of the compilation that made up the book “I, Robot”.
I called, I got permission, and they faxed the form to my professor’s office.
In our last week of shooting, 3 months after I received written consent to use the short story, one of the crew brought in a copy of Variety, which mentioned that a major studio purchased the book rights to I, Robot, and planned to make a film. Initially, I thought, “Awesome – free promotion!” Alas, that’s not what was looming on the horizon.
Somehow the legal team from the studio found out about a student project, in a small private college in the Midwest, with no budget, being shot in a warehouse basement, and decided to issue a cease and desist order. Basically, what that means, is that the studio’s lawyers said to us, “You’re using our property. Stop, or we’ll sue you into the stone age.” I responded by sending them the consent form from the Asimov estate, and explained that it was a student project, not a commercial venture worth litigating.
Instead of the letter recognizing our valiant efforts as students that I expected, I found myself on the tail end of a phone call that changed my life. I was contacted directly by the lead of the studio’s legal team, who explained my situation to me very clearly. He told me that I was technically in my legal right to use Isaac Asimov’s material. However, if I chose to proceed, they would file multiple lawsuits totaling over 2 million dollars against me. In the end, I might win, but it would take hundreds of thousands of dollars in legal fees just to fight it, but would cost them nothing more than the salaries they already pay their lawyers. It would be 10 years before any type of verdict could be levied, and by then it wouldn’t matter what the outcome was, since their film would be long since released.
So, when you say "Well, I can, but is it legal?", that's really the wrong question to ask. The right question is whether or not Lego will permit you to do so, and whether you have the money to defend yourself if Lego decides they won't let you do so.
I'll let you decide, for yourself, how likely Lego is to object.
Again, not a lawyer, not legal advice, get a lawyer.
(Disclaimer: segments of this were copied from a similar reply I made to a similar question.)
This kind of questions are usually answered by lawyers after a good amount of money, and not even them will tell you for sure. To be sure you'll have to meet a judge in a courtroom, which I guess is what you're trying to avoid :)
If Lego is actually public domain you'll probably have no problems as long as you don't use the Lego trademark/logo or anything else that isn't public domain.
Just because the basic LEGO patent has expired, that doesn't mean that all their other intellectual property is in the public domain, nor that the laws are the same everywhere you want to market your own product. If your game represents itself as being in any way remotely related to LEGO toys, the LEGO company or trademarks, you could face trouble.
If in doubt, come up with your own slant on the construction idea, or pay for proper legal advice.