While a part of us wishes this were a story about a new Lego brick that inflicts less pain when stepped on, that’ll have to wait.

Recently, Lego engineers have been hard at work developing recipes for cleaner, greener bricks.

The company recently announced a recycled brick prototype

Over the last 3 years, a 150-person team at Lego has tested 250+ formulations to create a brick from recycled plastics.

The prototype, which uses plastic from recycled bottles, is the 1st to meet Lego’s quality and safety requirements. According to Lego, a 1-liter plastic bottle contains enough plastic to make 10 2×4 bricks.

The hard part: building recycled bricks that are just as strong as the old ones.

Researchers have found that a single Lego brick can withstand 950 lbs. of force, or the weight of 375k bricks on top of it.