Unusually small burrows, i.e., tiny tubes that run through the rock ... Passchier et al, Subfossil Fracture-Related Euendolithic Micro-burrows in Marble and Limestone, Geomicrobiology Journal ...

Take a look at the Announcement Trailer for Marble Run Maker, a sandbox physics-based simulation game developed by Raikar Entertainment. Players will construct tracks made of room-centric items ...

So another idea that we've had is the fact that you could have a huge marble run - like an entire wall of your den could be a marble run. How does that sound? OCEAN:Really amazing. TONY ...