This is my mesh (the cube) and the goal is to extrude the upper part
The idea is to get THIS FINAL RESULTS BELOW:
In order to achieve this goal, I used ,as always ALT + S, but the result was this one:
My question is: Alt + s works perfectly with all the mesh i used before: why in this case, with a mirror, i get that distorsion? Is there a way to fix it?