To be honest i did try these before like 3 or 4 times. It never worked for me coz i was thinking like how to bend material into a sphere. But when you think about the material itself how would it react in the real world in the shape of a sphere u will notice that it worked for u. Like instead of thinking about fabric rolled in a sphere think what a fabric would look like thrown on top of a sphere? or a sphere looking candle? or a block of cheese in the shape of sphere?

This way ur min wont be thinking of bending up objects. It will be thinking about real life objects just happened to be spherical or a box or whatever shape you want. Give it a try and think of crazy shapes you would put these materials in its really fun :)