How to reformulate this in a CVX way: Cube over Square

For the record, here is the formulation for norm(y)^3/x^2, as provided by @Michal_Adamaszek at How to reformulate this in a CVX way

Declare a variable t , add the constraint geo_mean([t,x,x])>=norm(y), and use t in place of norm(y)^3/x^2