create a dice. With bolean operations.. Create a Cube.
Use the filleting tool. Press the + key, and hit return.
Create a sphere, rotate it.
Your sphere must be at the right scale, and at the right place. Use the proportional scale and move tools.
Select the sphere, choose the punch tool, click on the Cube. Use the + and - Keys todo display successively the diferent combinations between the two intersected objects. Press.
Return when wanted shape is shown.