pointlight light1 void 0 0 0 1 1 1

lambertian red   void 1 0 0
lambertian green void 0 1 0
lambertian blue  void 0 0 1

triangle t1 red   1000 0 0   1000 -500 500    1000 500 500        
triangle t2 green 1000 0 0   1000  500 500    1000 500   0           
triangle t3 blue  1000 0 0   1000 -500   0    1000 500 500