An optional array containing the sub-cells of this cell.
Mac Catalyst 13.0+
When specified, each particle emitted by the cell acts as an emitter for each of the cell's sub-cells. The emission point is the current particle position and the emission angle is relative to the current direction of the particle.
The default value of this property is nil.
The following code shows how you can create a firework style effect using sub-cells. The fireworkCell has an emission longitude of one quarter turn anti-clockwise to emit particles upwards. It emits trailCell instances which have a slight yAcceleration that simulates gravity.
Note that the scale and color of fireworkCell are inherited by trailCell.