The Brain puzzle is basically a pocket cube with funny-shaped pieces. There are no colours so, assuming that you can solve a pocket cube, your task would be to work out which pieces are which - a lot harder than you think when they all look so similar
There are lots of cheaply and badly made puzzles based on a 2x2x2 mechanism. Some, like this one, are fairly awkward to turn in comparison to your favourite speed cube. Like all shape changing puzzles, it looks a lot nicer when it's solved than when you scramble it.