Brain Out Level 138 How many triangles are there? Answers. One of the healthiest things we can do for our body is to keep our brain sharp. There are many options to do so but the most entertaining, time-killing and the beneficial option is to play the game Brain Out. It is a very popular brain puzzle game that offers challenging and cool brain teasers and riddles, that will test all your skills and exercise your brain. As soon as you start playing Brain Out, you will be amazed by the very cool and playful graphics, the visual style and the way everything is composed. The game offers daily rewards, daily challenges and tons of interesting levels with a variety of brain teasers and riddles.