Was it the rotation that was throwing you off? I had some troubles getting that to work properly and it might not be perfect.
I just went back and checked to make sure I wasn't imagining it. Sometimes the shapes change while you move them around. I had a shape that was a column of 4 and a column of 2. After moving it around a little, it became a single column of 4. It threw me a few times on my first play through (but ultimately makes the game easier because the shapes always seem to simplify). Hope that helps!