RotateTransform allows you to rotate an element at a certain degree specified by the Angle property. In the first image, no transformation was applied and thus it will look as default. If you compare this with the other images on the screen, the second image is rotated clockwise at an angle of 45 degrees. The third and fourth images are also rotated at an angle of 45 degrees, but with a small difference.
For the third image, the rotation was done at the center position (0,0). For the fourth image, it was done at the center position (30,30). Here's how the difference will look:
