Appearing Pencil

 On a yellow and blue flat surface there are two brushed metal knobs with pictures of muliple blue pencils.
A red and blue and yellow exhibit table with a purple and white information panel on top, sits in front of green and blue walls. On the table there are two brushed metal knobs with pictures of muliple blue pencils.

This visual illusion causes a pencil to appear, then reappear.

How it works

Count the number of pencils. Swap the panels and count the number of pencils again.

Things to try or ask around the exhibit

  • Did the number of pencils stay the same or change?
  • Where did the pencil appear or disappear?

Background

This is a type of Deland Paradox puzzle, which relies on arranging items incrementally above and below the 'equator' line, so that when the pieces are swapped over, an illusion occurs of one item (a pencil) appearing and disappearing.

Finding the science in your world

Magicians rely on 'loopholes' in visual perception to create illusions. By misdirecting a viewer's attention and gaze (or by relying on normal quirks of visual perception), a magician is able to introduce or remove objects, making them appear or disappear unexpectedly.