I'd probably just buy spray fabric paint and paint them.

I wanted each front to be different, sort of like a quilt effect but the colors are pastel. I think I like the idea of patterns more than a single color.

Well if you want them all different, fat quarters are a good choice.

The spray glue would work or they they have stick on hook and loop. It sticks really well.

I find stick on Velcro doesn’t give a smooth finish as spray glue does, because it has thickness.

I have the velcro circles. Is any brand of glue best or are they all around the same?

The fat quarters are a little bigger than the front so were I to use velcro I'd attach on the sides and bottom not on the face, good point Colleen thank you

I can’t offer brands as we have different ones in Australia to the US. Sorry.

I'm not clear on what these cubes are made of...are they a hard plastic?

If so and you didn't mind a more permanent change, you could decoupage them with mod podge. If you decoupage them, you could also select wrapping paper instead of fabric.

My concern with spray fabric glue is that the edges will get mucked up as you slide the cubes in and out, depending on how often you do that.

Another idea is to wallpaper the cubes. You could check and see as some wallpaper places have old discontinued books that they give away for free or for very cheap.

I think for longevity, keeping all the edges looking like they do the day you finish your project you want to use fabric glue. It will not only keep you pieces in place it will seal the edges.

Annie here is an example of the cube:

https://www.ikea.com/us/en/catalog/products/10382391/

Oh they’re fabric.

when you said fabric cubes, I’m such a crafter, I thought you meant to store fabric! Doh!

Mod Podge is the best. Even diluted Elmers glue will do the trick. You can jazz them up in sooooo many different ways ! Have fun !

I think decoupage is a skill, I tried it last summer and although my project did not turn out badly, neither was it the beautiful examples that people had posted of their own work in the thread at the time. I think I am going to use fat quarters and velcro. The advantages are that if I want to change to another pattern or back to the original I can, and also with some effort a particular piece can be repositioned. There are companies selling packaged fat quarters for crafts so I ordered some on Etsy.

I am going for a shabby chic bedroom look. Not everyone loves that but I do, but I could also see wanting to change back to neutrals at some point.

Since it's all fabric I would use iron on fusible tape. Put a strip of the tape between the two fabrics, apply iron heat on top fabric and it fuses them together. You can turn under the edges to get a nice clean finished edge. It can be removed by applying the iron again. I always used a thin damp towel between the iron and the fabric. It works perfectly. It is also very inexpensive. You can get it at any fabric store or store that has a fabric department.

https://www.hobbylobby.com/Fabric-Sewing/Sewing-Quilting-Notions/Fabric-Care-Dyes/Stitch-Witchery-Fusible-Bonding-Tape/p/80818735

Stich witchery is the brand I have always used.

I would fold the edge 1/4-1/2” and run an iron over it before you glue. I don’t think you want raw edges.

Yes you could use stitch witchery or you can just use your glue gun. I've glued fringe onto a number of my valances and it sticks really well.