Got a bit carried away with this video about pebbling a chessboard.
The video features Zvezdelina Stankova and was filmed at MSRI.
Here is part one:
And here is part two (part one is required viewing):
Here is a roughly-edited part three for people who are really keen:
And here is a section I cut from part one about the "invariant" - I thought people might it find interesting and it makes part one easier to understand…. but it also makes part one very long, so I chopped it!!!