In the ditch only. I don't believe it needs any more quilting. The shape and colors are the design.If any more quilting, then perhaps 1/4" inside the sashing strips between blocks but not the black strips in each block.

I did one a lot like that, and it was a quilt as you go pattern....

I agree. Simple and effective.

Thanks every one.
I have learned so much on this site from all the members .
Tom

I wouldn't use white. This is beautiful piecing work, and if you use white, that's all you'll see, I think.

I agree, use black, a decorative stitch in the sashing. I'd stitch in the ditch in the squares but only because that's about all I can do, not having FMQ experience or skills. Others have good ideas about what to do in the squares.

Very pretty. I made a king quilt in stained glass pattern and had it quilted w/a meandering stitch in black. Didn't take away from the design....

I agree with SITD with black thread on all the black parts. Then I think maybe just a small meander in the colored sections with a coordinated thread. Lovely little piece & look like you did a great job! Good luck with your quilting!

Definitely no white thread. Don't know if you've ever used invisible thread, but I've used it twice and will never use it again. Stitch in the ditch around all the sashing and the borders with black thread. I've been using the decorative stitches on my machine quite a lot lately. Either use black or a bright colored varigated thread to sew decorative stitches on the black areas.