The current game built in WebGL can be found here https://datbootcamp.com/classroom/perceptual-ability/top-front-end-visualizer/
A 3D object is generated, and three orthogonal view points are registered - Top to Down, Front to Back, Right to Left. Directly visible edges are shown as solid lines, hidden edges are shown as dotted lines (construction lines).
Two of the viewpoints are shown to the student, one viewpoint is used as the answer choices. The incorrect answer choices contain some variance from the actual missing viewpoints.
The current version of this is built in WebGL which has had some compatibility issues with browsers, and sometimes generates duplicate answer choices. The current game occasionally produces duplicate answer choices.
Please send an email to firstname.lastname@example.org if you’re interested.