My level of the moment

I recently came across "Patterns of impulse" which is not the kind of levels I like usually (not calm enough for me) but trying to solve it gave me a very good surprise, that I will try to explain here:

After having laughed at the show made by the impulse stones moving frantically (look also at "stay there" or "Bendixxon", the last one witout impulse-stones), I suddenly discovered the mystical truth about this level: It illustrates almost perfectly L. Boltzmann's kinetic theory of thermodynamics!

Howzsat? Well, just imagine the impulse-stones are moving particles (the free path anyway is not much: less than one unit length, wiz the length of a cell in the landscape) which constitute an amorph solid at the beginning of the level: Nothing moves so that the initial temperature is the absolute zero. Then comes Blackball who caresses slightly one of the impulse stones, and suddenly everything explodes! This can be interpreted as the solid suddenly melting (the fluid is not compressible enough to be a gas, but rather a liquid) and if ever Blackball tries to swim into this liquid, a brownian motion crashes him, so he'd better stay in one of the shelters. Finally after some time (and some help from Blackball here and there) the fluid cools down and freezes again, keeping a cristallike structure (more on this later) and freeing a path (hopefully) to the oxyd stones...

Usually, playing an Enigma level is being always active, and often rapid, which requires a lot of concentration and does not really let the player see what happens. But for this level, during the cooling of the fluid, one can observe several interesting phenomena:

When two impulse stones meet, say one moving to the right and the other to the left, they endure a shock like real particles, but the shock is perfectly elastic: After the shock, every one of the separating particles comes back to where it came, so that the total momentum is conserved. But if only one of the particles is moving, it gives its momentum to the other one, but instead of stopping, it comes back either:
The total momentum is doubled! We could call this a more-than-elastic shock. The "worst" case is when an impulse-stone hits the central stone of a group of three, which after the shock begin to move all of three, plus the initial moving stone, which comes back, so that the momentum is quadrupled!

When the stones don't move anymore, they tend by themselves to be arranged in a regular pattern, which we may call a cristal, and looks typically like this:
cubic cristal
I propose to call this cristal structure the cubic system because it looks like a cubic cristal viewed from above. In this cristal, the distance between two neighbours is twice the unit length. But there is a more compact, an rarer, cristal strucure which is stable (temperature zero), which I compare to the diamond structure:
diamond cristal
(one particle is missing on the lower line: impossible to move an other here without touching one of the stones of the middle line, which would ... arrgh!)
In this cristal structure, every particle has 4 neighbours like in the cubic structure,  but the distance between neighbours is the square root of 2, times the unit length: About 70% of the preceding. Actually there is a still more compact stable structure, where the space is completely filled with impulse-stones, but to build it would require much more pressure than Blackball could furnish. In this structure that I would be tempted to call the "neutron star structure", the distance between neighbours is simply the unit length, then 70% of the diamond and half of the cubic structure.

There is more to say about these structures: Imagine a row of impulse-stones in an otherwize empty terrain, each occupying a cell with odd abscissa: Cells 1, 3, 5, etc. Then along comes Blackball at position 0 who pushes impulse-stone at 1 to position 2: The impulse-stone excites the one at 3, who goes to 4 and sends it back to position 1. Then  the stone at 4 sends the one at 5 to 6, which makes it resume its equilibrium position at 3, etc.: What we see is the propagation of a pressure wave in this pattern, which I would call a phonon. I have also observed some kind of cavitation (bubbles of void moving in the fluid), and temperature fluctuation. One can even see the ice cristal grow in a still moving fluid, and sometimes partly melting. Also when two parts of the liquid freeze in incompatible cristal structure, a default appears in the cristal which can propagate in the solid...

All of this while waiting that the situation calms down!

Thinking to the moving switches of "how solid", "the Flagstone reaper" and "the dark outside", I begin to realize that Andreas has a dangerous gift to give life to strange creatures (half-robot and half-alien) and observe their independant evolution, not unlike the hero from a Mary Shelley book...

Brrr!

Alain