▁the ▁same ▁time . ▁For ▁example , ▁while ▁the ▁first ▁beam ▁passes ▁through ▁the ▁empty ▁box ▁to ▁hit ▁the ▁pixel ▁in ▁the ▁top - left ▁corner ▁at ▁the ▁back ▁of ▁the ▁box , ▁the ▁second ▁beam ▁passes ▁through ▁filled ▁box ▁to ▁hit ▁the ▁top - left ▁corner ▁of ▁the ▁bucket ▁det ector . ▁ ▁Now ▁imagine ▁moving ▁the ▁las er ▁beam ▁around ▁in ▁order ▁to ▁hit ▁each ▁of ▁the ▁pixels ▁at ▁the ▁back ▁of ▁the ▁empty ▁box , ▁mean while ▁moving ▁the ▁corresponding ▁beam ▁around ▁the ▁box ▁with ▁the ▁object . ▁ ▁While ▁the ▁first ▁light ▁beam ▁will ▁always ▁hit ▁a ▁pixel ▁at ▁the ▁back ▁of ▁the ▁empty ▁box , ▁the ▁second ▁light ▁beam ▁will ▁sometimes ▁be ▁blocked ▁by ▁the ▁object ▁and ▁will ▁not ▁reach ▁the ▁bucket ▁det ector . ▁ ▁A ▁processor ▁receiving ▁a ▁signal ▁from ▁both ▁light ▁detect ors ▁only ▁records ▁a ▁pixel ▁of ▁an ▁image ▁when ▁light ▁hits ▁both ▁detect ors ▁at ▁the ▁same ▁time . ▁ ▁In ▁this ▁way , ▁a ▁sil hou ette ▁image ▁can ▁be ▁constructed , ▁even ▁though ▁the ▁light ▁going ▁towards ▁the ▁multi - p ixel ▁camera ▁did ▁not ▁touch ▁the ▁object . ▁ ▁In ▁this ▁simple ▁example , ▁the ▁two ▁boxes ▁are ▁ill umin ated ▁one ▁pixel ▁at ▁a ▁time . ▁ ▁However , ▁using ▁quantum ▁correlation ▁between ▁phot ons ▁from ▁the ▁two ▁be ams , ▁the ▁correct ▁image ▁can ▁also ▁be ▁recorded ▁using ▁complex ▁light ▁distributions . ▁ ▁Also , ▁the ▁correct ▁image ▁can ▁be ▁recorded ▁using ▁only ▁the ▁single ▁beam ▁passing ▁through