TV Picture-in-Picture - (PIP) - (Window-in-window Viewing) - Picture-in-picture is a display system where programming (a TV channel) is displayed on the full TV screen simultaneously as one or more other programs (channels) are displayed in smaller windows. https://en.wikipedia.org/wiki/Picture-in-picture

Mosaic

Simultaneous Viewing - A collection of elements (channels) displayed in little windows on a single TV screen.