I found the pacific northwest basket weaver application tedious and frustrating to use. When I mistakenly placed a line across my triangles by reversing positive and negative numbers, I was unable to undo the operation. The "remove" option actually cleared the line with beige, deleting part of my previously-done triangle work. The fill-in-the-blanks interface seemed absolutely 1980's compared to current drag-and-drop technology.
Students might find a 3-D animation package to be much more engaging. Perhaps something on interpolating splines? (Without, of course, using the terminology, but just explaining to students that it can be difficult to fit a smooth curve through arbitrary points)
And as requested, here is my image.