Hi there. by looking at poop can a lay person tell with they have pinworms or a tapeworms?

You might be able to: Pinworm is about 1 cm in length and you might be able to see it. Tapeworm is very long usually and what you might see in the stool is its part of the body or the egg in the stool (looks like whitish seed)

Well: In general pinworms your tiny thread like white worms about an inch in length. Tapeworms are like flat spaghetti noodles there can be short segments. Consult Healthtap with photographs of stool with worms in it or see a primary care doctor in person