People walk passed sculptures by Chinese artist Minjun Yue on a street outside a museum in Beijing, China on July 5, 2018. (Photo by Nicolas Asfouri/AFP Photo)

Rice seedling festival is a traditional folk festival in longji, guangxi, China on June 9, 2019, during grain in ear season. (Photo by Costfoto/Barcroft Media)

Firefighters take part in the bodybuilding event during a firefighting skills contest at the National Fire Service Academy in Gongju, South Korea on June 13, 2023. (Phoot by Yonhap/EPA)

American TikTok star Charli D'Amelio attends CELSIUS Cosmic Desert Event at Coachella on April 12, 2024 in Indio, California. (Photo by Tommaso Boddi/Getty Images for CELSIUS Energy)

Everyone wants to get something for nothing - whether it's a lucky upgrade that means you can turn left when you get on a plane instead or heading off into the economy seats, or even getting a few extra features thrown in for free when you buy a new car.

As some of the sharpest businesses around, no-one understands this quite as well as casinos and that's why they all have a system that they call comps. It's short for "complimentary offers" and these are special treats specially designed to reward you for your loyalty to the casino in question. They're basically bonuses.

Shadow art is a unique form of sculptural art where the 2D shadows cast by a 3D sculpture are essential for the artistic effect.

Brick-carving featuring Tang Dynasty (AD 618-907) maids performing musical instruments is seen at the Chinese Music History Museum in Xian University of Architecture and Technology on September 27, 2008 in Xian of Shaanxi Province, China. (Photo by China Photos/Getty Images)

Vendors selling vegetables wait for customers under a flyover in the early morning in Ahmedabad, India on February 1, 2017. (Photo by Amit Dave/Reuters)