A fundamental question in early childhood mathematics concerns the relationship between young children's own informal signs and the formal abstract symbolic language of mathematics. This study presents research investigating the genesis of mathematical semiosis from a Vygotskian cultural-historical (social-semiotic) perspective. In this study we look at the premature stages of dealing with quantity and their relationships. Our aim is to reveal the interweaving of young children's sign-use and to consider the role of intertextuality in mathematisation. Longitudinal, ethnographic data were gathered from case studies of seven children aged 3-4 years in an inner-city nursery school in England, documenting observations of their spontaneous pretend play. The data are interrogated through interpretive analysis and show that some graphical signs moved between individuals' texts, also borrowed from others including the teacher, and woven together. Children's progressive understandings of mathematical sign-use appear to be attained in part through intertextual exchanges in social and culturally meaningful contexts, such as pretend play.