If the size of a space is measured by counting the number of places available for a particular activity, rather than by using an absolute measure such as the square metre, then small people may find the world larger. Size measured by number of places becomes a function of the size of the user, and the form of this function suggests that the everyday environment has a fractal dimension, a single number which may be associated with architectural qualities. This measure was tested with an experiment based on children playing hide and seek and was used to explain some illusions of perception of size.