Using the left mouse button, select piece and drag into position. Pressing the right mouse button rotates piece. If you need a hint, press the "V" key to view the whole image. Change the number of pieces: 9 | 24 | 48 | 160.
These "corpuscular rays" result from the difference between the sunlit section of the sky and the shadows created by the clouds obscuring the sun. While the sky may appear clean, it is actually full of tiny particles which scatters sunlight. The rays appears where the sun continues to shine (and is scattered) on these particles as compared to the unlit particles in the shadow of the cloud. To learn more about clouds go to JetStream - an Online School for Weather.