translation.en: Your efficiency goes down with more bounces, because you lose about 10 percent with each bounce, but this allowed us to collect light from a plus or minus 25 degree angle.
translation.zh: 效率随反射次数的增加而减少， 每次反射将损失10%的能量。 好处是，光线角度的接受范围扩大了正负25度。