Enter lower-case "r" and "y" from keyboard to rock and brighten model.

Note how each Arsenic atom (purple color) is bonded to 3 Sulfur (Arsenic coordination number = 3), and this group of four atoms shows pyramidal geometry.

Note how each Sulfur atom (yellow color) is bonded to 2 Arsenic (Sulfur coordination number = 2), and this group of three atoms shows bent geometry.