LEGO Brick: The Tubes UnderneathHow hidden cylinders created the perfect grip.

From the show

Why it looks like that

Early stacking toys fell apart at the slightest touch because they relied solely on gravity to stay upright. The addition of hollow cylinders inside the bottom of LEGO bricks introduced "clutch power" through interference fit. This precise friction keeps structures stable while allowing them to be disassembled, revolutionizing construction toys.