How I draw a lightbulb - realistic drawing

Drawing a realistic bulb using light and shadow Final picture: Materials used: heavyweight gray paper, 9B, 7B and B pencils (Caran d’Ache grafwood), paper stomp, colored pencils (Caran d’Ache Supracolor Soft), fibre tip pens (Staedtler Noris Club 320 Double Ended Fibre Tip Pens) markers (Tria Letraset), white charcoal pencil (52 Carb-Othello 1400 Schwan) black and white acrylic (Decoart and Pebeo)