“The fluid will be able to flow from one point to another if and only if there is a connexion without dams between them, and this will be so if and only if there is an undammed self-avoiding walk connecting them (i.e. a walk which visits no intermediate point more than once). It is, therefore, appropriate to study the self-avoiding walks in crystals.” (p. 631) #Broadbent #Hammersley #Self-avoidingWalk