LEGO

To me, especially when it comes to MOCs, it’s like an art form to work within the limitations of what the branded medium provides, or with digital MOCs, what the branded medium could hypothetically provide. Using offbrand or custom pieces to embellish a LEGO structure feel like “cheating” in a way to me, both in the artistic aspect and the engineering aspect. I’m fine if people want to make communities for Megablox for example, or communities for any or all building blocks brands (excepting ones which support plagiarists like Lepin), but a forum for a branded item/medium should be almost entirely built with brand. There’s also what’s called a generic trademark, wherein a mainstay brand’s name becomes a common term for a type of product (ex. “Kleenex” in lieu of “tissue”), that I’d want to avoid since it makes it harder for clear communication among hobbyists and worse for the brand (and in this one case, I generally do like the brand).

Great summary of the Constitution's IP clause.

Patens are expired, bricks are fair game to copy.

Sets designs and appearance are copyrighted so for sure copies of sets is piracy.

I prefer only Lego brand bricks. Sometimes I buy bulk bricks for my son at a local used Lego store and there are always a few off brand bricks. I usually remove them and throw them out. They don't go together as well sometimes, and all the time the colors aren't quite right. Even if the color does match, the color fades a little and always fades differently on off brand bricks. Just prefer the real thing.

The used Lego store has used bricks in bulks for $6 a pound, and you can pick and choose what pieces you want. For three bucks you can get half a pound of rare, genuine bricks, if you know what you're looking for. Great value.