Heads up! This blog post hasn't been updated in over 2 years. CodePen is an ever changing place, so if this post references features, you're probably better off checking the docs. Get in touch with support if you have further questions.

CascadiaCSS, “A CSS conference for the Pacific Northwest,” just wrapped up earlier this month. I SO WISH I was there, because they had one of the coolest ideas ever: CSS Layer Tennis with CodePen!

Layer Tennis was invented by Coudal and typically involves Adobe Creative Cloud stuff and passing files back and forth. Moving that concept to CSS is a no brainer, especially with a tool like CodePen where you can just fork the previous Pen.

Check out a collection of all the weird results. We gotta try this at a meetup sometime.