Experimental filmmaker and animator Len Lye’s N or NW, created for the GPO Film Unit in 1938, sets opening titles as handwritten messages on plain white envelopes. A moving camera explores the enclosed world of two quarrelling young lovers attempting to settle their differences by mail in barely-glimpsed interior locations. Focussed tightly on faces, and the physical process of letter-writing, isolated features: a nose; a mouth, momentarily appear through artfully cut, rounded-edged and abstract-shaped holes in full screen-size hand-written letters. The postal journey is represented by superimposed footage of a pillar box, tipping from side to side against background foliage, followed by a shower of envelopes, falling against clouds. A rap on a door knocker signals the letter’s arrival, and once differences are resolved, the protagonists expand their world to an outdoor, shared summertime idyll of swimming, sunbathing and a single kiss among river-set swans. A final handwritten message reading ‘Yours, the end’ fills the screen, to the sound of a knock at the door.