You will be shown two websites, one on the left and the other on the right. You can interact with them normaly, click buttons, make inputs, route to other pages, etc.

By dragging the middle line to the left or right, you can resize the websites to your desire.

If you think you have see enough of both websites, it is time to pick your favourite. By clicking the "Left" or "Right" button on the bottom of the page, you choose the website on the respective site to be the better designed one.

Overall you will see 8 different websites, competing in a tournament like structure to see wich one you think is the best.

Try it out on the example below: