oPeriscope

oAt hairdresser's

oState-money box

oKaleidoscope


oA mirror or a window?

oA glance in the distancel

oUniversal mirrors

oMirage


oThree-dimensional goat

oBubble sphere

oPenguins

oFibre-optic cable


oEntomologist's microscope

oTelescope

oA magic eye

oBattery stall


oColourful tops

oSunglases

oSvarowski's sphere

oCounterfeit banknotes


oChromatic glasses

oCD spectrometer

oSoap bubbles

oInvisible beams