Puzzle helps to learn Cartesian coordinate system (x,y) and practice to calculate sums over the line (the very first step to understanding integration). Sound: switch Ring/Silent controls speaker. After 30 seconds quick shake to restart the puzzle or reveal the answer with just a tap.

In Gradients puzzle each cell has a value that contributes to the sum when calculated along a row or a column. Additionally, the value of each cell depends on the direction of the summation ("anisotropic field"). Sometimes, the clues can be satisfied by different pattern of orange cells. This means that, without additional information, solving the puzzle may involve a guessing step. An interesting phenomenon is the formation of "isomers", where an alternative solutions can be created by inverting a subset of cells. When playing for fun, any of the isomers is considered a valid solution. However in Competition mode, one more clue is added: a sum along the main diagonal. This additional clue helps distinguish between isomers.