In 'Eternal Sunshine of the Spotless Mind' there is an ice scene around the beginning of the film where the two main characters lay down on the ice. Screen left there is a unique and very beautiful 'crack' in the ice.
Bonus features on the DVD emphasize less special effects (mostly for the set).
So how did they get the crack in the ice? Was it artificially created? Did the production crew happen to search and then found it (aligning with Director's style)?
Trailer provided shows topic question at 1:41