The study reported in this paper contributes to the exploration of the development of children's mathematical drawing. 36 preschool children produced drawings of 'something tall and something short'. Open-ended analysis of the forms and structures of the drawings revealed four categories ranging from scribble to the base-line comparison of two objects. The variety in drawing forms and the scattering of ages across the four categories suggests that educators should be more aware of children's drawing development in association with their skills in creating mathematical representations.