For millions of adults and kids, LEGO can do no wrong. The sets based on properties like Star Wars, Harry Potter, and others are engaging, fun, and even work as an investment opportunity.

But LEGO isn’t totally satisfied with world toy domination. They’d like to be friendlier to the environment while doing it.

LEGO recently announced a commitment to develop a LEGO brick made from recycled polyethylene terephthalate (PET) bottles. This is no small feat: A recycled brick needs to prove itself to be as sturdy as a traditional brick made of acrylonitrile butadiene styrene (ABS) plastic, with structural integrity and enough “clutch power” to grip other bricks.

Out of 250 different kinds of PET plastic tested over the past three years, LEGO has discovered one that seems to fit the bill. Their process [PDF] involves grinding down the bottle so it’s reduced to granular flakes, which are then cleaned and processed for durability. (The exact method is something the company appears to want to keep a trade secret.) The material is molded into bricks and then winds up on shelves.

Here we see science being performed on the eco-friendly LEGO brick.LEGO

It’s estimated that for every 32-ounce beverage bottle recycled, LEGO could make as many as 10 4-inch-by-2-inch bricks. The company hasn’t yet disclosed whether entire playsets could be made of recycled plastic, or just random bricks.

LEGO has been turning toward a more environmentally friendly business model for some time, with plans to make its manufacturing carbon-neutral by 2022 and its packaging sustainable by 2025.

Some challenges for the eco-brick remain. LEGO will need to devise a way of using color dyes on the recycled material. It will also need to be compatible with all existing LEGO bricks.

Currently, the brick is in the prototype stage. A testing phase is expected to last for a year before the company heads into a pilot phase. Finally, they’ll need to make sure test subjects are left howling in agony after stepping barefoot on a recycled brick. If all goes well, the eco-brick will make it to stores in the not-too-distant future.

[h/t Mashable]