Add links to information about transformations

@@ -72,6 +72,10 @@ A slightly old but still worthwhile post about rusts standard traits.
 [3d vector mathematics](https://vvvv.org/documentation/3d-vector-mathematics)
 [sin appr. with fractions](https://dsp.stackexchange.com/questions/46629/finding-polynomial-approximations-of-a-sine-wave)
 
+# transformations within a coordinate system.
+[migenius](https://www.migenius.com/articles/3d-transformations-part1-matrices)
+[tutorialspoint](https://www.tutorialspoint.com/computer_graphics/3d_transformation.htm)
+
 # more math...
 
 A whole lot of interesting stuff about continued fractions: