One of the most fascinating phenomena in early development is that babies not only understand signs others direct to them and later use them to communicate with others, but they also come to direct the same signs towards themselves in a private way. Private gestures become "tools of thought". There is a considerable literature about private language, but almost nothing about private gestures. Private gestures pose an intriguing communicative puzzle: they are communicative, but with the self. In this paper we study two types of private gestures (signs) before language: (1) private ostensive gestures and (2) private pointing gestures. We show in a case study of one child between 12 and 18 months of age that both are used with a self-reflexive function, as a way of "thinking" what to do, in order to solve a problem in the conventional use of an object. The private gestures become self-reflexive signs.