The number 3 rears its beautiful head again.
Improvisation implies a knowledge of relationship between elements and a desire to create something with those elements outside or different from the elements themselves.
Experimentation, the step before improvisation, also implies a knowledge of elements but less of a desire to create something outside of or different from those elements. Experimentation is the use of/ investigation into the elements to discover their possible relationships.
The step before experimentation is exploration – the discovery of the elements themselves.