JezzBall

JezzBall is a computer game in which red-and-white 'atoms' bounce about a rectangular field of play. The player advances to later levels (with correspondingly higher numbers of atoms and lives) by containing the atoms in progressively smaller spaces, until 75% of the area is blocked off.

JezzBall was introduced in 1992 as part of the Microsoft Entertainment Pack, and also in the later Best of Windows Entertainment Pack, and despite Microsoft withdrawing support in 1996, it still has a significant fan base.