Leonardo da Vinci’s encrypted writing style

In Girl in the Glass, James receives a postcard from Mr. Tesla, at first the young analyst finds the written poem impossible to decipher. However, the postcard pictured a bird, drawn by da Vinci in his Codex on the Flight of Birds, giving James a hint on how to read the secret message. The poem, written as a mirror image, requires the text to be written from right to left, opposite standard English style, with each letter reversed. To read such text, one must hold it up to a mirror. 

While some speculate this was a form of encryption to safeguard his ideas and scientific observations, potentially from theft or repercussions from the Roman Catholic Church, other theories suggest it was a practical method to prevent ink smudges since da Vinci was left-handed. 

However, handwriting analysis suggests da Vinci may have been ambidextrous, capable of writing with both hands. Examination of da Vinci’s inscriptions revealed he could write with both hands, his left following a mirror-written pattern and his right employing the standard left-to-right style. He likely learned to write with his right hand at a young age, even though he was born left-handed. Historically, the left hand was considered bad luck or evil, in fact, the Latin adjective for left is “sinister”. It appears mirror writing was a conscious choice by da Vinci, rather than a necessity, likely to keep his ideas private.