Hi guys! First time here!
So basically, I’m making a Particle System that’s supposed to spawn rectangular shapes. So I’ve implemented a of (65,65,100)VectorParam to create the rectangular shape, into BoxMask-2D and then into an Emissive shader, which looks great in material preview but as soon as its stuck into the pSys it seems to break down to it’s original square shape, anyone have any idea whats going on? Sorry if this is really noob and Im probably missing something really apparent. 
Thank you in advance!