Here is my opinion about designers and teachers: some are great designers, some are great teachers...and it is a RARE thing that one person wears both hats. You can design, or you can teach. Not both. Each is a "gift" from God. I don't think it can be learned.
IMHO, you were ripped off. I'm not suggesting "on purpose", but the class was a monumental waste. The pattern was a waste, the "teaching" was a bigger waste.
I've been there, done that. Wasted money on classes. It is my BIGGEST PEEVE ever.
LATE TO CLASS?
She should have given a refund of $15 to everyone in attendance. I would have.
Even 10 minutes late is inexcusable. She should have set her timer to be there 30 minutes
to set up her class, and gather her wits. 45 minutes LATE?
If I'm takin' money from folks, they are gonna get their money's worth and then some.