170mm x 244mm Collerton c10. tex V3-11/21/2014 5:28 P. M. Page 221 10. 1 INTRODUCTION 221 Figure 10. 3 Funnel and spiral hallucinations generated by Lysergic acid diethylamide or LSD. Source: Reproduced withpermissionof Nature Publishing Group. Figure 10. 4 Funnel and Ssiral tunnel hallucinations generated by LSD. Source: Reproduced with permissionof Nature Publishing Group. Figure 10. 5 Cobweb petroglyph. Source: Reproduced with permission of Nature Publishing Group.