Heartknots 1.0 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. Heartknots for Mac relates to Theming Tools. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software.
From the developer:
Jamie McCanless returns with five heart-shaped Celtic knots for those whose love so deeply entangles the small roots of their hearts that even the strongest wind that blows shall not separate them (thus John Long described "Indian courtship" in Canada during the 18th century). In other words, Happy Valentines Day from warrior~poet.
An iContainer of this set is also available at warrior~poet.
You may want to check out more software for Mac, such as agua or Can You Jump It 3D, which might be similar to Heartknots.