The tumbler die cut pieces are a snap to work with. I think the tumbler that is being talked about is actually called tumbling block..or something like that..it is three trapazoids, each a different color, that when sown together with a Y seam give the illusion of three dimension....right?

I now have a different interpretation of what you're saying. They do have opposing angles. When you sew the rows together, you have to turn the row in the other direction for the angles to meet evenly. If you have a tumbler with a smaller angle as your first tumbler and the row that you want to put next to it has the wider angle, you need to turn that row basically upside down to get the two wider angles to meet, and then every tumbler going down will meet its appropriately wide tumbler.

This is not tumbling blocks so no y seams but I am having trouble with the seams matching. This may be the first one I actually toss.

tumbling block
 

I guess you are doing the tumbler. I thought you were doing the tumbling block which to me is like a 3 D cube so my comments were not at all on the quilt you are doing. I did a tumbler with all chevron/zigzag prints that really was a cool quilt. The pic below is the tumbling block quilt I am working on right now and thought that is what you meant.

I tried one of these a couple of years ago. Cut everything out then realized it was not going together the right way. Put it away and have not touch it since. Post pics when done.. please.. and good luck.

I'm not really able to follow what everyone is saying, but if you just want to get the points to meet, and they're slipping as you sew, I recommend gluing the places that need to be joined with a spot of Elmer's Washable School Glue, then pressing that spot with the iron to dry it. That will keep it in place when it's sewn.
Don't know if that helps, but I use that method for joining points all the time.

Carol, yes, using the Washable School Glue really does help with those difficult seams.

Craftsy has a free BOM quilt that includes the Tumbling Block. It was the 2013 BOM class and you could still enroll and select that specific block for the lesson on it. Might help you with method of putting it all together. I thought it would be very difficult but now it is one of my favorites.

Yes, Elmer's glue...good thought. I just might try that and not have to scrap the whole quilt. Thanks!