The objective is simple, all you have to do is to align the orange rectangles on the guiding line by tapping on the columns where the orange rectangles are moving.
Tapping on a column will instantly change the direction of the selected rectangle.
You must tap right when the rectangle is over the guiding line. If the rectangle is properly aligned on the guiding line, it will turn green.
There are unlimited number of levels. How far you go it all depends on how fast you react.