Wavy design on laser side of cds??

[ninetynine]

I noticed some wavy smudge design on the laser side of my compact discs. I even bought new cds which already had this. They seem to play fine , but what would explain these designs? It looks like they were dipped in some liquid and the liquid would have left a mark.

 

[Balthazarr]

Do you mean you bought new blank cd's or factory recorded?
I think the waviness is due to diffraction and refraction.
If you change the angle of disc does the pattern shift?

 

[motaboy]

I know what you mean, some CDs just come like that.
I always wondered why it's caused, but I assume is some sort of pattern that forms when they "splash" that aluminium material on the back of the CD.