Where can I find the sound effects `clack.wav` and `pen_click.wav` that are used in some of the videos?

[vanleefxp]

Dear Grant Sanderson,

I am a follower of 3Blue1Brown and liked your videos very much. From your videos I find joy in learning Mathematics. Recently I am working on a python program that is a simple game running in the command line. I would like to add some sound effects to my program, and it came to me that the clack.wav effect in clacks.py and the pen_click.wav in windmill.py used in your videos sound awesome. I flipped through the directory of this project but couldn't find these two sound files. May I have these two files if it is available. Thank you very much!