VIDEOS:
Stone knives and bearskins
While stuck in the 1930s, Spock has to create a massive crude circuit array for his tricorder to display its recordings from the Guardian of Forever, and he complains that he has to work with the 1930s equivalent tech resources of "stone knives and bearskins."
Example of:
Bamboo Technology
Edith Keeler Must Die
Example of:
Godwin's Law of Time Travel