What causes droplets to run upward (in relation to the Leidenfrost effect)?

Question

-I can understand why droplets of water "float" on a hot surface. The effect was already discovered in 1751, by mister Leidenfrost, and bears the eponymous name, the Leidenfrost effect.
Here one can see that droplets of water run upwards as if they climb a ladder. How does this work? How do the droplets grab themselves to the next step and pull themselves up? In the video, no explanation is given.

It is clear that energy is given to the droplets by the hot underground and the same effect (climbing droplets) can be seen as kinetic energy is given to the droplets by shaking the underground, or varying the cohesiveness of the underground (see here). I'm interested though only in the case where the Leidenfrost effect is at work. How can the droplets move up?

Answer 1

In the usual Leidenfrost effect droplets levitate because of pressure of steam beneath them. Here the mechanism is the same but because the surface has notches, the resulting force is up the inclined plane. To see it, consider the system "dropet+steam", pressure force acting on it should be perpendicular to the surface of the notches, which is up the plane.

If you want to think about it in energy terms, it is like a steam engine: because of heat steam is produced and it expands until pressure becomes balanced with the droplet weight. During this expansion it does work which goes into increasing the potential energy of the droplet.