The Solar Impulse 2 airplane, flown by test pilot Markus Scherdel, flies off the coast of Oahu during a test flight from Kalaealoa Airfield in Kapolei, Hawaii, March 3, 2016. The solar-powered plane is ready to continue its revolutionary voyage around the world. After the craft was grounded in Hawaii last July due to overheated batteries, it was repaired and upgraded, and a recent initial test flight proved successful. (Photo by Eugene Tanner/Reuters)

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.

Artist Princess Tarinan von Anhalt throws paint into the flow of air coming from the engine of Flexjet’s Learjet 40 XR engine to create a painting on a canvas at Signature Flight Support in West Palm Beach, Florida. The artist associated with the Jet Art Group used the help of Flexjet and their plane to spray paint on a canvas to create distinctive paintings to celebrate the 50th anniversary of Learjet. (Photo by Thomas Cordy/The Palm Beach Post)

“The Antonov An-124 Ruslan (NATO reporting name: Condor) is a strategic airlift jet aircraft. It was designed by the Soviet Union's Antonov design bureau. It is the world's largest ever serially-manufactured cargo airplane and world's second largest operating cargo aircraft. During development it was known as Izdeliye 400 in house, and An-40 in the West. First flown in 1982, civil certification was issued on 30 December 1992”. – Wikipedia

Photo: The new metro called “Bombardier MOVIA” with 22,50 meters long and 3,2 meters wide is load on a Antonow An-124 plane for transport to India on February 25, 2009 in Parchim, Germany. (Photo Handout Bombardier Transportation via Getty Images)

Nadezhda Tolokonnikova, a member of the feminist punk band, p*ssy Riot, right, reads papers at a district court in Zubova Polyana 440 km southeast of Moscow in Russia's province of Mordovia, Friday, April 26, 2013. A Russian court is to consider whether one of the jailed p*ssy Riot members is eligible for early release. Nadezhda Tolokonnikova, in custody since her arrest in March 2012, is serving a two-year sentence for the band's irreverent protest against President Vladimir Putin in Moscow's main cathedral. Tolokonnikova's lawyer Irina Khrunova is at right. (Photo by Mikhail Metzel/AP Photo)

Using body paint and a woodland like location, Gesine appears to have created a model to look just like a red panda, Dortmund, Germany, October, 2016. An artist brings animals to life using body paint and contorted models. At first glance, these images could be mistaken for portraits of wildlife in their natural habitat were created with paper and paint. However, they are actually the incredible works of illusion by talented body painter Gesine Marwedel, who paints models to creates realistic animals. (Photo by Gesine Marwedel/Barcroft Images)

Like a scene from a fantasy movie, a dilapidated room that appears to have been literally ripped out of a building remains suspended in mid air above Nantes, France. Its walls were torn apart, revealing bricks below the plaster, and wood floors reveal the joists inside. The floating room is accessible via a ladder. The gravity defying surreal installation is the work of Argentinean artist Leandro Erlich. The large-scale piece, called “Monte-meubles – L’ultime déménagement” (literally - The Furniture Lift – The Ultimate Moving Out), was created for the biannual Le Voyage a Nantes, an art festival which turns the entire French city into an art gallery.

In order to get a glimpse into the visual culture of drug trade in New York City, a British photographer Graham MacIndoe collected more than one hundred bags, which were used to sell heroin. These bags feature references to various movies, fast-food restaurants, and luxury brands. This could be a way to mark various purities of heroin, or maybe different drug dealers use different markers to distinguish between each other. We can only wonder where Graham has acquired all these heroin bags. Hopefully, he picked them up after their contents were emptied. (Photo by Graham MacIndoe)