A crystal is a type of directed graph encoding representation theoretic information. The crystal I will discuss is called the Heisenberg or <nobr></nobr> crystal, originally defined by Shan and Vasserot. Its vertices are multipartitions, and its arrows arise from a categorical action of a Heisenberg algebra on cyclotomic Cherednik category O. The representation theoretic meaning of this crystal is to keep track of one part of the support of simple modules. There are two crystals needed to determine supports; the other is the <nobr></nobr> crystal. Likewise, Dudas-Varagnolo-Vasserot recently constructed categorical actions of these two crystals on the unipotent category of finite classical groups in order to classify Harish-Chandra series. The problem of computing the arrows in the <nobr></nobr> crystal was reduced to a combinatorial problem by Thomas Gerber. I will explain the solution to this problem: the rule for the arrows, and the rule for determining depth of a multipartition in the crystal. This is joint work with Thomas Gerber.