Answer:
u always follow me but I am rarely seen
I move without wings Between silken string I leave as you find My substance behind.
By Moon or by Sun I shall be found. Yet I am undone if there's no light around.
My first is in some but not in all. My second is in tiny but not in tall. My third in little but no in big. My fourth in port but not in pig. My whole is made in nature's way. For clothing rugs used every day.
When it comes to me, you go on red and stops on green. What am I?
When is it bad luck to see a black cat?