The shapes are used to test whether a real human being is logging into our site. You see something like this on many websites -- it's called image verification, or a captcha. We have the captcha to prevent hacker software from being able to log into our site, "scrape" information about shops, and repost them on an unauthorized website. The "captcha" has to make it hard for hacker software to "read" and spot the correct shapes, but easy (we hope!) for a human.