Unknown X, does not react with bromine or with dilute  Upon treatment with potassium tert-butoxide, 

Xgives only one product, Y, Unlike X, Ydecolorizes bromine and changes  from purple to brown. Catalytic

hydrogenation of Ygives methylcyclobutane. Ozonolysis–reduction of Ygives dialdehyde Z, Propose consistent

structures for X, Y,andZ.Is there any aspect of the structure of Xthat is still unknown?