where oh where did the sippy cups go?

I just found one under the bed , one in the toy box ,one in the dresser dawer and one a tote bag ! Around here you can find a sippy almost anywhere. I swear everyday we go on sippy hunt downs and we find them in some strange places , dds even tried flushing them ! Im still missing 1 cup and dd swears she didnt have it ...I wonder where its hiding? Maybe I will check the washer or in a shoe? Kids are pretty crafty when it comes to hiding things.I think finding a needle in a hay stack would be alot easier to find then a sippy in my house.