Baby Bib Pattern Help

I want to make a baby bib for a friend of mine and found a picture of a really nice one. From the picture I pretty well can see how to knit it without a pattern except for one part. It has 2 ridges, then some hearts, then 2 more ridges. I think they did the ridges by knitting the red and pink yarn together in garter stitch to make it thicker but I’m not sure. If anyone has any ideas about how they made the ridges it would be a lot of help. It’s the top bib in the picture.

The ridges are made with garter stitch. What I think they did was knit a row of a new color, then purled the next row and then knit a row with the old color. Hmm… or they could have just purled the new color first… Not sure though you might have to experiment on swatch.