Spline+ is an extension of the Spline game where the users can, instead of adding a ball, move one of their balls, as long as it does not have more than one other ball resting on it. Both Spline and Spline+ are played on the Shibumi platform.

Shibumi is the essence of beauty, or elegance in its minimal form. A shibumi object may appear simple but will reward the viewer with hidden depths as it is explored over time. Shibumi is simplicity hiding complexity.

Games and puzzles based on square pyramidal stackings have existed at least since Edouard Lucas' cannon-ball stacking problem of 1875. The most famous 4x4 square pyramidal game is Pylos (published by Gigamic). Shibumi is different due to the third ball colour, drop mechanism, different numbers of players, lack of a board gutter, and the fact that it's a system for playing many games rather than the embodiment of a single game. Some Shibumi games may be playable with a Pylos set but many will not.