I used the pattern from July 2016 Prima Magazine* to make this matching top for the PJ pants.
I used purple buttons from the stash which toned quite well with the purple spots between the pandas. I hand sewed them on using matching purple thread so that they have a solid purple circle appearance.
*Prima magazine is a UK general women's magazine which includes a simple free pattern every month. Subscribers get it included with the pattern, but I think if you buy it from the paper shop you have to send off for the pattern and pay postage.