I'm trying to think of some good names for this interface & its one method.

It's not filtering the sketch, it's filtering the word places. It's almost a mask for the places. Maybe WordPlaceMask, or WordPlaceFilter?

And maybe `contains` or `canFit` would be a better name than `filter`.

Finally, I want to think about the interface - it might make more sense to pass a rectangle. I'm not sure yet how "public" these filters will be - if they're visible to end-users, I'd really like to get the interface right.