multiple scattered light but to go deeper we have only multiple to scatter light left so you cannot afford to reject multiple to scatter light otherwise you will get no signal so we have to use those tortuous paths for our light propagation and somehow we have to get spatial information right so that's the huge challenge because oftentimes when photons wander around through this tortuous path you'll lose spatial information so that means you're not gonna get a sharper image we somehow have to form a sharp image our solution