It’s well known that people can’t keep count of a collection of things, once there are more than about four of them (in a straight line).
This is a practical problem for eg primary schoolteachers who have to lead a class of youngsters on a school trip, for example. One technique which is often adopted is to encourage them to hold hands with a partner…the thinking presumably is that it is much less likely that a group of two independently minded little people will disappear without causing some kind of noticeable fuss. Hardly an approach to security which a parent would find reassuring.
Today’s invention is a reflective harness of the type commonly adopted by schools but which has a clckable, child-safe catch attached to the front and rear of the waistbelt via a short lead. These can be used to attach one child to another in ‘indian file’ formation.
In order to help with safe road crossing etc, each harness could also have a clip on either side (with shorter leads). The harness on child n+1 could thus be rotated front to back so as to link with one side clip on child n, thus enabling a cross-linked two-by-two formation of tractable length (as well as linking children n-1 and n+2 etc of course).