Triakis octahedron

A triakis octahedron is a 3D shape with lots of sides and corners. Imagine a big, big ball made of lots of smaller balls stuck together. Each smaller ball has 8 corners and is called an octahedron. But instead of being just one big ball, it's like some of the corners have been cut off and replaced with new smaller balls. These new balls also have 8 corners and are called octahedrons too. This makes the whole shape look like a big, bumpy ball with lots of corners and edges. It's a bit like a giant snowflake made of lots of smaller snowflakes!