As of this commit all "pages" will be 2-sided. There's a new class CurlPage, using which you can assign a separate texture on both sides, one for front side only, or same texture can be shared on both ...

Curl/cylinder is defined with three parameters, position, which is any point on a line collinear to curl. Direction vector which tells direction curl 'opens to'. And curl/cylinder radius. 'Paper' is ...