I still, for some reason, can't upload pictures. Is anyone else having that problem?
Because of the photo problem, I won't be able to show you a picture of the final mystery quilt steps but, I think that the diagram/photo on step three should be sufficient.
Mystery Quilt Fourth and final step
Continue adding strips following the picture in step three. The last row will not have the white triangles at the end. When you have this row in place, sew the rows together as you have them in the layout.
Before doing that, make sure you have sewn the sections in each vertical row together to make long strips.
When all the strips rows are sewn together, trim the bottom so it is even with the shortest strip lengths. Remember that this last row does not have triangles.
Press the top and finish with border strips, layer with backing and batting and quilt. Bind using your preferred method.
I will post a photo as soon as I am able. I would love to see your finished project.