Z took a moment to work through what Gerard had said.
"So, it's like the mental version of when I'm combing different Arithmatical equations or rune sets? That makes sense, to use properties of both spells-vocalization and mental visualization-to get one result. So if I..."
She aimed for a smallish bush not too far away and tried to cast the spell. She could feel the magic from two different spells trying to combine, but it didn't work.
"Blast. Or, well, not." She frowned and tried a second time. This went a little better, some snow did end up flying off the bush, but it wasn't anything like the small controlled explosion Gerard had created. This time she had noted seeing the dull red she associated by Expulso.
"Hey, Gerard? Can you cast that again slowly? I might be able to see how the red and Silencio are combining, so I can duplicate that and then figure out how it feels to combine spells like that."