Add punctuation: In this area Stepanov extended work by Poincar
A: In this area Stepanov extended work by Poincare .

Add punctuation: But we should not do with narcissus tuberose and lily petals of which may turn black from the procedure
A: But we should not do with narcissus, tuberose and lily petals of which may turn black from the procedure.

Add punctuation: Eliminate the middle cubes by adding cubes of edge
A:
Eliminate the middle cubes by adding cubes of edge.