Lego the company was fiercely protective of their IP. They had a patent they regularly enforced. Once the patent expired they took MegaBlocks to court trying to

Lego the company was fiercely protective of their IP. They had a patent they regularly enforced. Once the patent expired they took MegaBlocks to court trying to claim the shape of their bricks was trademarked (they lost this... but took it all the way to the Canadian Supreme Court).