and this is blu-tack! Yes, that - now mostly blue - putty-like paste which is versatile, reusable, pressure-sensitive and adhesive produced by Bostik. Its main purpose is/was to attach papers/posters ...

Blu Tack is a sticky, putty-like adhesive, used to adhere items in place. For example, Use Blu Tack in lieu of a nail or tape, to place pictures, poster or notes on the wall. If Blu Tack is spilt on ...