I just reported a bug, but I'm wondering if I missed something somewhere. In Unit 3, Lesson 7, Puzzle 11, students are asked to make the 2nd alien shake like the first. The problem is that the variable block that makes the first alien shake is not available in the block view. It is an easy fix in the "show text" view, but there is nothing that would make a student decide to go there - like a hint in the instructions.
Like I said maybe I missed something in a previous lesson or I have a blind spot in this lesson, but I was very confused... until I figured it out.