I think about Mary every day. It's a fleeting thought. It's a - "I wish she was here to talk to, I wish she was here to tell about X, to ask what she thinks about Y, to share a laugh about such and such." She is like when I notice the moon coming up, or Venus appearing in the cold winter sky. I miss her and then move on. Or she is like someone walking briskly across a screen I am watching. She's like a bead on the thread of my day. There's no telling when she'll appear, but appear she does.
I am fortunate to have had such a friend.