Introduction - If you have any usage issues, please Google them yourself
1. How that game interface (that is, 20* of 10 grid) 2. Box that way, that is, the coordinates of the four small box set: one box is the origin coordinates (0,0) on the right side block coordinates (1,0), the following box coordinates (0,1), and so on. 3. Rotation Formula: (x, y) after rotating 90 degrees is (-y, x). Since x-axis to the right, y axis, the so produced a clockwise rotation effect. Four. Important idea: Do not rotate the formula have the means to rotate. 5. Fireworks trajectory tracking.