Downloading OSLay 1.0 for Mac from our website was free. OSLay for Mac lies within Education Tools, more precisely Science. The actual developer of this free Mac application is Universität Tübingen.
From the developer:
OSLay is the optimal syntenic layout of unfinished assemblies. The whole genome shotgun approach to genome sequencing results in a collection of contigs that must be ordered and oriented to facilitate efficient gap-closure. The tool uses synteny between matching sequences in a target assembly and a reference assembly to layout the contigs (or scaffolds) in the target assembly.
You may want to check out more software for Mac, such as UN-SCAN-IT Demo, ScienceMatrix or Geometer's Sketchpad 5, which might be related to OSLay.