You can't pass that list. That would be a type error. The list must be (List :t), and :t can't change from element to element. In other words, it's not valid if

You can't pass that list. That would be a type error. The list must be (List :t), and :t can't change from element to element. In other words, it's not valid if you can't fill in :t. A rotation has type :t = Rotation; a dilation has type :t = Dilation. It can't be both at the same time. If you wanted to be able to do this, you'd either (1) need a more powerful type system, or (2) express all kinds of transformations into a single sum type.