I had a lot of fun playing with values for this block. I kept trying to put a light blue in it and my husband finally said, "It really doesn't have enough light blue for it to work." Trust the engineer to get right to the point! And he's right, there isn't enough of the light blue for it to work. So I picked out the different shades of pink instead.
As I've been working on this project I have realized that the large dot has to be a dark fabric. It certainly helps to make sure that other colors beneath it don't bleed through and the dark value seems to tie the block together.
I had a lot of fun playing with threads on this block too. The outer petals are blanket-stitched in Sulky Rayon 40 weight thread. The inner petals are stitched in Bottom Line thread by Superior Threads. It's a 60 weight thread and I love how thin the line is. Bottom line also has a low-sheen to it and so the fabric can stand out. The darkest pink fabrics are both blanket-stitched with Deco-Bob by Wonderfil Threads. It definitely has a lot of sheen, which I like for emphasizing the dot.
The inner petal fabric that has pink lines on the purple background gave me a lot of trouble. I couldn't figure out what color thread to use on it. I tried the three below. I ended up ripping out the first two because they just didn't work. I think the lighter pink worked well because it blended with the darker pink fabric behind it. The white lines in the photo below are bits of stabilizer that I forgot to brush off.
The little dot at the very bottom gave me trouble too. The background of it is a very warm lavender, but the dots on it are a cool lavender. I had to go with one or the other and my thread choices were very limited in light lavender. I ended up using Coats and Clark Dual Duty Plus which is 37% cotton and 63% poly because it seemed to be the right color. You can see from the picture below the thread is kind of a combination between the two. A pinker thread would've brought out the background of the dot more, whereas a bluer thread would'be brought out the dots more. I didn't want to go too blue because the rest of this block uses very warm threads. So I ended up with the final color as a compromise between the two: a little blue, but not too much.
Overall, I am very happy with my pink and purple possibilities and my four-year-old loves the block.