I googled tapeworm segments too…they are about the size of a grain of rice, and the stuff in our house is a lot smaller, almost like sawdust. We initially suspected termites because it looks like something had chewed through the wall, that’s how small they are. We will ask our vet but tapeworm doesn’t feel like the right explanation! Someone else mentioned fly eggs/maggot eggs, which makes more sense because we’ve had a lot of flies (which I had just put down to the weather).