I read this book a long time ago (in the early 90s). It's a ghost story about a girl (whose name I think may have been Victoria or Vicky) and a boy in the classroom who is able to see her. From what I can remember, the title refers to how she'll appear by walking into the room through a pink wall. I wish I could remember more of it or find it again! As a child I enjoyed it; it was spooky and old-fashioned without being scary.