Okay, I have to admit that this was a difficult Etsy search for me. As soon as I read the word "complement," I got this mental image of Danny and Sandy singing, "We go together..." Once that was in my head, I couldn't seem to shake it.
And for anyone else who has thoughts of John Travolta and Olivia Newton-John dancing around in their heads, someone has created a cute journal from a recycled Grease album cover:
Denise's interpretation of this word was much more appropo - yin and yang as perfect complements of each other. She found a number of good examples. (See her comments on my previous post.) I think the yin yang baseball is my favorite, though.
Once I was able to banish the singing Danny and Sandy from my head, I came up with these two items. The first is a pair of ceramic cruets that seem to melt into each other. Visually, they are complements of each other, but I found the artist's description to be particularly fitting to this word. She describes the pair as a couple, the strengths of one supporting the weaknesses in the other.