Driving myelination by actin disassembly
(Phys.org)—If a metallurgist wanted to determine how a blade was made they might cut a small cross section, mount, polish, and etch it, and then look at it under a microscope. They could probably tell right away whether it was forged, cast, or perhaps even 3D printed. If the blade was of a particularly high quality, like a Samurai sword, they could see the multiple layers that were created the through laborious cycles of heating, hammering and refolding that are typically used to optimize the grain structure for both toughness, hardness, and grain orientation. The point here is that the structure evident in the Samurai sword cross section didn't just passively polymerize out of thin air like a snowflake, or get made by some other passive thermochemical series of events, it took a more directed driving force.