To convey the three dimensionality, mass and volume of forms on a flat surface varying shades of light and dark . What is the name of this technique

.                                       sorry i just need points

the artist used rapid brushstrokes.

"prior to 1910, these new artists were called neo-impressionists, and they believed that "modern paris" was the proper subject for their paintings."

this is the text provided by the program, disregard other answers, as they are confusing and based on loose knowledge of the subject.   : )