Hi Aditi, U can try with 3 or 4 triangles joined with each other..

Hi Aditi, It's quite difficult to implement sphere with thermocol bt nt impossible if u r ready to do some work then u can try with this.. u cut ur thermocol into pieces just like piece of football.. n join it in a way that it will create a sphere.. i m not able to explain u more clearly becoz i can't attach a screen shot here.. n it might possible that there will a better way to do this.. bt the soln comes into my mind so i told u..