Scheme Cad is described as 'programmable 3D CAD tool that currently supports wireframe models and features animation. Users can program Scheme Cad by writing extensions in Scheme (a dialect of LISP)' and is an app in the Photos & Graphics category. There are more than 10 alternatives to Scheme Cad for Windows, Linux, Mac, Self-Hosted solutions and Online / Web-based. The best alternative is FreeCAD, which is both free and Open Source. Other great apps like Scheme Cad are OpenSCAD (Free, Open Source), BRL-CAD (Free, Open Source), CadQuery (Free, Open Source) and Antimony (Free, Open Source).
BRL-CAD is a powerful cross-platform open source solid modeling system that includes interactive geometry editing, high-performance ray-tracing for rendering and geometric analysis, image and signal-processing tools, a system performance analysis benchmark suite, libraries for...
OpenJSCAD.org is a more up-to-date OpenJsCAD frontend where you can edit .jscad files either locally or online via JS editor (built-in). A few functions are available to make the transition from OpenSCAD to OpenJSCAD easier (OpenSCAD.