In 1978, LEGO's major patent expired in the US (20 years after it was filed in 1958). It opened the door for additional competitors, which LEGO was understandably concerned about. In 1984, the first major competitor surfaced in the US market-- Tyco Super Bloks. read more
And because the Kiddicraft bricks were never patented in Denmark, LEGO was free to make their own version-- the Automatic Binding Brick. And sure enough, LEGO's version was incredibly close in appearance to Kiddicraft bricks. Nearly identical. It turns out, LEGO's patent in 1958 was an enhancement to the brick-- not a new product. read more
LEGO claimed that they owned the"look" of the LEGO brick. But Tyco hit them where it hurt. At the time, everyone quietly believed that LEGO's 1958 patent was revolutionary, and that it was what created the small plastic building brick toys. Tyco proved otherwise. read more
The patent did what it was supposed to do: it protected Lego's invention for a limited time, and then it expired, so that anyone could make compatible products. That's the patent bargain: in exchange for asking the government to keep your competitors at bay, you agree to let the public copy your invention for free when the period of exclusivity is expired. read more