So you're familiar with these, then? Another one of your friends?

[ he sweeps his hand in a circular motion, as if tracing a circle in blue light with his palm. another portal's drawn forth, nearly opaque with no hint as to where it leads. ]

In any case, you're half right. They're capable of being as big as I wish -- although at a certain point, it just takes too much of my energy for me to manage unaided. [ a little smile! ] There're tricks for that.