Gridly

A tile in a grid needs to answer to four things at once: its own cell, the row it sits in, the column it sits in, and the grid as a whole. After Effects allows a layer exactly one parent, so parenting cannot express that. gridly composes the four transforms with expressions instead. Each control is a null carrying a Rest point, and what the rig reads is how far that null has been moved, scaled or turned away from its rest. Those offsets are applied cell first, then row, then column, then master, exactly as nested groups would. The upshot is that dragging a row null slides that row, scaling a column null spreads and enlarges that column, and turning the master rotates the whole arrangement, all at the same time and without any of them fighting.