Perfect Balance is a physics puzzle that is about stacking and balancing pieces of various geometric shapes so they don't fall down. There is an iOS version of the game available in Apple's App Store, as well as several sequels and spin-offs.
The game is about stacking pieces of various shapes. On each level, there are static geometric shapes and the player is given pieces that needs to be stacked on top of the existing structures. The goal on each level is to stack the shapes so that they don't fall down. All pieces can be rotated and you may place them in any order. None of the pieces can rock back and forth as they need to be perfectly balanced in order to beat the level. The physics engine allows you to balance shapes on a single point, creating stacks that would never stand upright in the real world. Scoring is dictated by a subtracting counter, so the faster you do the puzzle, the more points you receive.
There are two difficulty settings, both of which has a level set with 40 levels. In order to unlock the "Inferno" level set, you must first complete all 40 levels in the "Harmony" set. The "Harmony" difficulty setting has a soothing setting with calm music and background pictures of microscopic particles. Once you reach the "Inferno" setting, additional pieces to balance are added to each level and the setting changes. The pieces become bloodstained, the background picture resembles a hotel room and the music changes.
The game series inspired a spin-off series called Imperfect Balance where the goal is to tear down towers consisting of the same geometric shapes that you used to build towers with in the Perfect Balance game series.