Robert Walser was a very important Swiss writer who also inspired Kafka, but died many years after Kafka. He was a loner all his life and died during a walk in the wood near the asylum where he spent some 15 years. He was autistic. He used to write in "micrograms" little pieces of paper with the same pencil. It took 25 years to decrypt his last novel (The Robber, in the English translation). The novel I liked most was The Assistant .
here is one of his micrograms.
You should know German to read it, but probably it would take one year to decipher it.