JezzBall is a computer game in which red-and-white balls, referred to as atoms, bounce about a rectangular field of play, or room. The player advances to the next level (with correspondingly higher numbers of atoms and lives) by containing the atoms in progressively smaller spaces, until at least 75% of the area is blocked off. One gains a bonus for eliminating more than 75%, which is calculated from the percentage over 75% that one manages to block off. One must do this while racing against the clock. It is similar to Qix, which was released during the Golden Age of Arcade Games.
JezzBall was programmed by Dima Pavlovsky and introduced in 1992 as part of the Microsoft Entertainment Pack, and also in the later Best of Windows Entertainment Pack. The game is named Jezzball after Jez San, who was a contemporary of Dima at the time. Despite Microsoft withdrawing support in 1996, it still has a dedicated fan base. While JezzBall is available from many abandonware sites, there are several open source and shareware clones of the game that can be legally obtained. No fewer than eight such clones exist, covering nearly every major desktop and PDA operating system.
The purpose of the game is to contain the atoms within a room at most 25% the size of the initial room. By using the left click to create walls and the right click to rotate the direction of the wall-building device (WBD), the user must contain atoms in smaller and smaller rooms. When a room is made that contains no atoms, the room disappears. The amount of black on the screen is displayed as a percentage, and when this percentage reaches 75% or more, the level is won and play proceeds to the next level. The first level has two atoms, and each subsequent level has an additional atom. There are an infinite number of levels during play, so that one can never "beat" the game. However, there are only 49 distinct levels, and upon beating the 49th level (containing 50 atoms), the subsequent level is merely a repetition of the 49th level.
The player begins each level with the same number of lives as there are atoms in that level. To say that a life is lost when an atom hits a wall in progress of being built is inaccurate, because in fact, two lives can potentially be lost each time a wall is being built. The location of the cursor on the screen defines where the wall will originate, and this position can be terms the WBD. When initiated, two beams of "potential-wall energy" extend from the WBD as rays (in the mathematical sense) until reaching the perimeter of the current room. These two rays operate independently of each other. Upon reaching the perimeter without being hit by an atom, a potential energy ray (depicted in either red or blue) turns black and now serves to further section the room. Should an atom collide with only one of the extending energy rays, that energy ray disappears and a life is lost, but the other energy ray continues extending towards the perimeter. Should an atom collide with the other energy ray, another life would be lost. However, should the second energy ray reach the perimeter of the room, a partial wall will be produced. Two lives are also lost if an atom collides with the energy rays at their combined source (where they meet). It should be noted that the corners of the head of each energy ray are protected from being hit by an atom.
The fact that the two energy rays produced by the WBD act independent of one another is the basis for the stovepipe method of atom capture, and may speculatively be the only method of play that will allow advancement to higher levels. This is because, as the number of atoms increases, it becomes increasingly more difficult to remove parts of the room. Stovepipes are made by intentionally allowing an atom to hit one of the expanding energy rays (thus sacrificing a life) while making sure the other energy ray does in fact succeed in producing a partial wall. The closer the WBD is to one side of the room, the higher the risk is of losing one energy ray to an atom collision, and at the same time, the higher the chance is of securing the other energy ray of producing a partial wall.
As a player improves his skills, he can risk placing the WBD farther away from the perimeter wall perpendicular to which he intends to produce the partial wall. The photos below depict horizontal stovepipes; but vertical stovepipes can also be constructed, horizontal stovepipes allow for more capture potential, as the room begins with a longer width than height. Additionally, because each stovepipe costs a life, economy is key, especially in higher levels. With practice, players will be able to construct stovepipes that are 75% or greater than the length of the entire dimension of the room. To do this, the player needs to learn how to time the click so that an atom hits the small energy ray and not the long energy ray.
The best possible stovepipe is one or two boxes in thickness. Because the WBD always produces walls on the lines of the grid of the room, the two-box thickness is thus two half boxes surrounding a full box. After creating a stovepipe, the WBD should be switched to the other direction and placed at the tip of stovepipe. While lurking there waiting to ambush an atom, the new partial wall in the room (the one made to produce the stovepipe) will inevitably alter the path of the bouncing atoms, sending some of them into the stovepipe. Depending on the skill and experience of the player, the atom can be trapped at the end of a stovepipe in a little 3x3 room (actually, there is only one full box, as the peripheral 8 are all partial boxes). The atom will then be left bouncing from corner to opposite corner. Truly skilled players can click in this box without losing a life, thus locking the atom in a room so small that it can no longer bounce but only rotate. This method produces the most points, as the field of play is entirely eliminated except for minimal room necessary to actually contain the dimensions of the atoms. After using the entire length of the stovepipe to trap atoms, another stovepipe can be constructed.
In the earlier levels, the time it takes to trap atoms can be decreased significantly by eliminating the area of the room that was sectioned from the stovepipe by the partial wall, as depicted above.
It happens to be that while the WBD is engaged in producing its bidirectional energy rays, an attempt at producing another wall simultaneously will yield only one energy ray. This is key for a few reasons.
First, in the event that one sacrifices all but one life trying to stovepipe and still has too many atoms to catch, another stovepiping exploit would sacrifice the last life and the game is over. However, if it's possible to ensure that a full wall can be built without running the risk of having an atom hit either energy ray, a stovepipe can be created by simultaneously clicking the WBD, because secondary WBD engagements only produce one energy ray.
Secondly, When players reach level 20, for instance, there are so many atoms that even moderately sized stovepipes are quite difficult to make. Players should be happy with constructing stovepipes that are only long enough to catch two atoms each. Sometimes, such as on level 30, even this is difficult, and random clicking will naturally produce a stovepipe of some small length at the expense of a few lives. Doing this a few times will sacrifice an exorbitant number of lives, and each life lost is a potential stovepipe. Using this method of simulatenous stovepiping allows for sacrifice-less stovepipes. However, a player needs to possess the skill and experience necessary to quickly place the WBD in a good location to produce a stovepipe that is both a sufficient thickness and length and that won't be hit by an atom.
Clones of the original JezzBall normally offer updated graphics but vary slightly in timing and scoring from the original.
Many of these clones are shareware, limiting non-paying users to only a handful of levels. Many of these are found on JezzBall.com, an unofficial JezzBall page that is at least partially funded through the sale of these clones. Others, including IceBreaker and KBounce, are crossplatform, free software, open source games that are available on a number of operating systems. Some are skinable; The open source Icebreaker's default skin varies radically from JezzBall, using Tux, the Linux mascot, in place of balls. Silverware Games' Jezz Cubed offer dramatically different interfaces from the original JezzBall, adding three dimensional play, giving the player a cube to reduce by growing planes instead of a plane reduced by lines.