Tetronimoes 1.6 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program lies within Theming Tools, more precisely Screensavers. This free Mac app is an intellectual property of Opanoid. We recommend checking the downloaded files with any free antivirus.
From the developer:
This screen saver show Tetronimoes moving within a 3D (OpenGL) area and is an update to a previous screen saver with a name change. A tetromino is a geometric shape composed of four squares connected orthogonally. This is a particular type of polyomino like dominoes and pentominoes are.
You may want to check out more Mac applications, such as scarytime v9, Christmas Tree Creator '04 or System47, which might be related to Tetronimoes.