I would like create this cake bit I can't understand how to do the class spacer, and what is stopping it from pushing down in the 2 their![postimage id="4141" thumb="900"]

Though the pic is not clear I would guess the 'spacer' is a styrofoam dummy 'cake'.  OR it could be a glass jar.  What holds it up is a support system.  Could be as simple as plastic drink straws or dowels or hidden pillars and a plate.

It is a glass. So basically its a jar with dowels underneath the glass jar..

Yes.