&gt; <i>Their formation is driven by the atmosphere around them, and the relevant properties of the atmosphere (like temperature) are continuous, so the same on both sides of the snowflake.</i><p>So what you&#x27;re saying is that basically the ability to make twin snowflakes (by manipulating the conditions) proceeds from exactly the same circumstances which already makes their six branches identical?<p>Based on that hypothesis, you&#x27;re likely to get twins if you simply grow them in adjacent spaces: together, those spaces are still small and the atmospheric properties are even across them. And that&#x27;s what he seems to be doing.