The logo needs to be clear at 16x16, 24x24, 48x48 sizes.
As mentioned, the extension crosses out the word impossible and replaces it with the word, possible on all web pages you visit when you have it installed. It's more fun than functional, but still quite serious :)
Somehow in a small amount of space, you need to convey the message that "nothing is impossible".
That's really it. Nothing is impossible! How would you describe or illustrate that for someone visually. That's your goal!
Thank you so much for considering this project.
All the best,