STOS 1.04 was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The program's installer file is generally known as SquareTOSquare.exe.
This PC program is suitable for 32-bit versions of Windows XP/7. The actual developer of the software is Ty Harness Consulting. The most popular version among STOS users is 1.0. STOS lies within Photo & Graphics Tools, more precisely 3D Design. We cannot guarantee that the program is safe to download as it will be downloaded from the developer's website. Before launching the program, check it with any free antivirus software.
From the developer:
The square-to-square frustum is probably the most common sheet metal transformation. There are many applications: boxes, trays, moulds, hoppers, skips,etc. Trays and skips are very often tapered to allow for stacking and moulds for concrete lintels or fence posts are all slightly tapered to aid release. If you're in the welding and fabrication industry then you've, probably already, made a 1000 hoppers because they are used absolutely everywhere.
You may want to check out more software, such as STO Keybinds, gljakal's ToDo or Star Trek Online, which might be related to STOS.