Find the volume of the solid whose base is the region between the curve $\displaystyle y=x^3$ and y-axis from $\displaystyle y=0$ to $\displaystyle y=1$, and whose cross sections taken perpendicular to the y-axis are squares.

I don't understand "whose cross sections taken perpendicular to y-axis are squares".

How can I solve this problem? If possible, would you please explain step by step?

Thank you very much.