Blek

Blek is a puzzle game in which the player draws a "snake-like" black line on the screen that is recorded and played back like a pattern, recurring repeatedly across the screen. The object is to draw a line such that it will remove colored dot targets when it repeats across the screen without hitting a black dot. Lines that travel off the top or bottom of the screen reset the level, while lines that travel off the left or right of the screen reflect back towards the dots. Aside from repeating the player's drawn pattern, the stroke mimics the player's pace in drawing the stroke.

The game begins with no prompt or tutorial other than to use a finger on the screen and experiment. The first puzzles are "on open, white canvasses" where the player can solve the simple puzzles "by accident". The 80 levels progress in difficulty and require more complex solutions. Added elements include a "chain reaction" dot that launches other dots when struck. Its sound consists of a "whoosh" that accompanies the traveling stroke, a "chime" when colored dots are hit, and a human "disappointed grumble" when black dots are hit, resetting the level.

Blek was built for iOS by brothers Denis and Davor Mikan. While both had coding experience, neither had experience in game development. This was their first game together as kunabi brother. Denis had published short stories and a novel, and Davor released music on independent media label Crónica Electrónica.

Davor previously made Flash games and developed the idea for Blek from this experience. He approached Denis about converting the video game Snake for touchscreens, and Denis returned with the idea of "a line representing an idea that springs to life after it has been drawn". This thought was likely inspired by the calligraphy and ink drawings in a book by Japanese poet Matsuo Bashō that Denis was reading. They had several prototypes by mid-2013, when Davor joined a Parisian artist in residence program, where he felt he was treated differently when he introduced himself as a game developer instead of as a musician.

Blek received "generally favorable reviews", according to video game review score aggregator Metacritic. Though the game first released in December 2013 to little fanfare, critics "widely praised" the game, and it became popular in April 2014. It appeared in the top ten paid App Store games chart in April, reached the top by May, and was listed into June. Blek received a 2014 Apple Design Award and was featured in their Indie Game Showcase.

While it had sold 30,000 copies by February 2014, upon being featured in the App Store, it sold 500,000 copies by May, and over a million copies by June. Edge compared its aesthetic to iOS puzzle game Hundreds. Reviewers praised the game for the amount of freedom it affords its players.