Why do wombats make cube-shaped poop?

Deep in the Australian bush, there's a fuzzy, grumpy-looking marsupial with a secret superpower. The wombat can do something no other animal on Earth can do: it poops perfect cubes. Not round pellets like rabbits. Not logs like bears. Cubes. Little brown dice scattered on rocks and logs, stacked like the world's weirdest Lego blocks.
Why cubes? It starts with what wombats eat. They're grazers, munching dry grasses and tough roots all night long. That fibrous plant stuff moves slowly through their incredibly long intestines — the slowest digestion of almost any mammal. A single meal can take two whole weeks to become poop. During that crawl, their gut squeezes and squeezes, wringing out every drop of water and nutrition.
