The company was last year stripped of the right to keep the brick's three-dimensional 2x4 shape as its EU trademark, after a challenge from Mega Brands.

The EU's trademark office, OHIM, granted Lego the legal right to the shape in 1999, but then agreed with Mega Bloks' case that a brick was a functional, technical shape which could not be owned by any one company.

Lego has already lost one courtroom bid to win the rights back, and its lawyers return to the European Court of First Instance in Luxembourg again on Tuesday.

They will argue that Lego brick design contains characteristics that set it apart from others - such as the design and size of the studs on top of the bricks.

The company is challenging the previous OHIM decision, upheld by judges, that functional shapes, such as a brick or any other "industrial design" must be excluded from trade mark protection.

Otherwise, the court argued, one company would have a monopoly on a basic shape which could be deemed to be "necessary to obtain a technical result"

Lego claims that competitors do not need to copy the shape of the Lego brick to achieve the same "technical solution", and that most consumers identify its studded brick as the company's brand.

Editor's note: Unlike some sites, which told readers to stay away from Mega Brands (along with showing dodgy photos), I say this: This is capitalism working well: competition, with competitors competing on quality and price and consumers having options.

The plastic building block we associated with "LEGO" was actually invented and sold in the late 1940's by an English toy designer named Hilary Page under the "KIDDIECRAFT" brand. He failed to patent it outside the UK and LEGO started manufacturing them without acknowledging their origin.

After Hilary Page committed suicide, LEGO purchased the expired patents from Page's estate so they could pretend they invented them in the first place.

LEGO did invent and patent the little tube on the bottom of the brick, which wasn't in Page's original design, which allows for more connection possibilities. Once that patent expired, other companies, such as Canada's MEGA, (creator of Mega Bloks) created clones. LEGO, of course, sued for trademark infringement. In the US, they lost, because you can't trademark and patent the same things - functional elements, which are covered by patents, can't be trademarked. Other countries treat this issue differently, hence LEGO enjoys some trademark protection even for the purely functional elements.

Apparently, LEGO's view is that a patent should be valid as long as the company holding the patent continues to manufacture the product, and tends to be pretty aggressive about it. The irony they they effectively violated the patents of the original inventor is completely lost on them.