This is an animation I made for a new customer recently.
The 2D animation was realized in Flash, and then applied as an animated texture to a rotating 3D book in Blender.
This is a fun example of using Blender as a complement to Flash.
The background’s moving clouds we’re created by applying animation to “Noise Textures” and using those to distort the UV Map vectors, which I then input into a “Musgrave Texture” (if anyone’s interested in playing around with it, I’ve attached the sky animation .BLEND file).
looping_sky_animation_FIXED.blend (538.6 KB)
Feedback appreciated 
Peace and God bless!