I created this portrait with one light source, and here is how I did it.
I used one 5 ft photek soft lighter umbrella with a strobe inside.
One black foam core board for the background, and two white foam core boards on both sides of the model. I placed the light source above the model and about 1 ft away from the model, and that was it.
One light source? Yes, but multiple ways of manipulating said light source to achieve what I was looking for.