I love Bargellos too but have no space for a design wall in my sewing room. I went to a Dollar Store & bought 2 sheets of foam core. I layer them & tape them up to something. In my case to a set of metal shelves that hold my stash. If the tape lets go I just add more tape. It may not be perfect but I made a queen size double heart using my "wall". When done, I store it behind a chair.

If you're designing your own, I did it without a design wall. i drew the basic shape on a sheet of graph paper, and decided how wide the strips should be - I used 1", 2" and 3". i took another sheet of graph paper and colored stripes on it, similar to the colors of the fabrics I wanted. Then i cut the colored strips perpendicular to the changes in color and taped the colored strips to the shape I wanted on the paper. To make it easier to piece accurately, I then labeled the columns of strips with left and right for the direction I wanted to iron, so that the columns of strips would lock together when pieced.

I haven't done a bargello with a mirror image effect, but that would be designed in halfs or quarters. Neither have I done one where both dimensions change width.

I used my bed to lay the strips out in order of sewing.

Choosing fabrics is daunting. Took me forever to pair all of my fabrics, luckily my quilt shop was patient and helpful

My design 'wall' is the floor. I spread a sheet or fleece throw and lay out the strips or blocks and number them. Of course, I sometimes have to roll it up(blocks and all) so we can walk through! LOL