Being stuck at home, bored, desperate and coming up with a lot of weird ideas, a friend asks you to develop a tool to measure his ocular skills: one of those [Monoyer charts](https://en.wikipedia.org/wiki/Monoyer_chart) that ophthalmologists use.
Generate a board where each new letter is harder, bigger, bolder and stronger!
Write the function `generateLetters` which creates 120 `div`, each containing a letter randomly picked through the **uppercase** alphabet, and whose style properties have to be increased:
You only need to create & submit the JS file `harder-bigger-bolder-stronger.js` ; we're providing you the following file to download (click right and save link) & test locally: