Why dont the present shapes of the continents fit perfectly into a super continent

The present shapes of the continents fit perfectly into a super continents because for example,try fitting south america≠africa together it would actually fit. here is an image: 

Ithink it is space that makes up 70 percent

Evidence peice 1: millions of years ago existed the supercontinent pangea after millions of yearsnit broke into peices and formed smaller continents and islandsevidence peice 2: there is a massive fault line in san fransico and california that has the potential to cause massive earthquakes which supports the theory of fault linesevidence peice 3: mountains are said to be formed by earths tectonic plates crashing against each other for millions of years and eventually if forms a big point know as a mountain.evidence peice 4: the mariana trech is the deepest place (so far) discovered in the oceans of earth. it is so deep that you can literally see how earths plates are divided and or continents as well