light
d_light
    (
    vector freq = 10, offset = 0;
    int whichnoise=0;
    )
{
        vector PP,newcolor;
        float r,g,b;
        
        PP = wo_space(Ps)*freq+offset;

        if (!whichnoise) {
            assign(r,g,b,anoise(PP));
        } else {
            assign(r,g,b,noise(PP));
        }
        
        set(newcolor,r,g,b);
        Cl = newcolor;   
}