i'll try, though spookymemer90 is the one that made it:
The Shapeverse is the 3rd universe to be created. most objects there are simple shapes. This universe was created by The Double Pyramid long ago. squares are the most common to be alive in the shapeverse, while circles are most commonly planets and stars. there are many other shapes that serve different purposes. And one day 2 stickmen in the Stickverse were having a fight, and one of them threw a star at the opponent. They missed and the star was thrown fast enough to escape the Stickverse and collided with the Shapeverse! strange things happen when foreign objects get crashed into the Shapeverse like that. So the star became John Cipher! He gained powers from this, it is thought that Bill Cipher got powers like this somehow.
That's all I know. spookymemer90 can explain the rest.