From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Photographic record of five samples showing the progressive distortion of a circular pattern at different numerical stages.
| Identifier | WestWitteringFiles\V\December1930-February1931\ Scan118 | |
| Date | 24th December 1929 guessed | |
| VGVI 500 1100 2600 3100 4500 | ||