25 is the answer

This is a musical puzzle experiment that was created as part of the Assembly Game Jam 2017 for the HTC Vive. It is kind of a crude experiment on a puzzle mechanic I´m hoping to develop further if it doesn´t prove too hard for non-musicians.

You score maximum 9 points by throwing cubes through a gate.
To do so you must understand 25/4.

Tell me how many points you got and how many runs did it take!