phi phenomenon

The phi phenomenon is a visual illusion where a series of still images shown in quick succession appear as smooth, continuous motion. For example, in a flipbook or certain movies, individual frames are displayed rapidly, creating the perception of movement even though each frame is static. This occurs because our brains fill in the gaps between images, interpreting the sequence as fluid motion. The phenomenon demonstrates how our visual system combines rapid changes over time into a cohesive experience of movement, and it is fundamental to how movies and animations create the illusion of motion from individual still pictures.