Self-taught artist Oscar Ukonu makes monochromatic hyperrealistic portraits of people using nothing but blue Bic pens, selling up to $600 per piece. Each portrait takes weeks and several pens to complete. Before beginning his work, Ukonu takes about 100 photos of his subject and narrows it down to around 20 images to use as reference. When sketching, he uses three major techniques: hatching, cross-hatching and scribbling. This way, he can sketch and shade with precision, creating masterpieces out of ordinary office supplies.