Common steps and sub-activities

Watching helicopter blades

Helicopter blades can also provoke a spiritual experience via the light flickering through the helicopter blades as they rotate.

Clearly this  is a serious concern, as they could [and have] cause hallucinations and as a consequence accidents.

Occasional Paper No. 1; The Early History of “Non-Lethal” Weapons - Neil Davison
December 2006,  Bradford Non-Lethal Weapons Research Project (BNLWRP)
Department of Peace Studies, University of Bradford, UK

In the 1950’s investigations of US military helicopter crashes found that the pilots had become disorientated by the stroboscopic effect produced by the sun shining through rotating rotor blades.