Originally Posted by MadMorbius
Patent and trademark law is pretty big. But as I understand it, it comes down to an identifiable trait. If you can uniquely identify something based on a trait, and the trait itself is not in common usage at the time of the trademark, that trait can be trademarked.
In addition, it also has to already have a brand association to be trademarked.
For example, you can't just draw a random logo and apply for a trademark. Patents cover a process (unless it's a US patent, in which case it covers every fucking thing conceivable) and can be applied for regardless of the market status of your process. Trademarks have to be brand identifiable.
This is one reason why two completely different companies can actually have similar logos or slogans -both trademarked- so long as their products are completely different and an average consumer would not confuse one brand for the other.
So two technology companies, both making similar products, would likely suffer trademark wars like Apple & Samsung. However, if the two companies were a medical imaging equipment company and a mechanical water pump company, their products are so different that consumer brand confusion would be unlikely to occur, and thus could have similar trademarks.
At least, that's what my limited understanding of trademarks says.
Copyrights are different yet again.