Spearman concluded that performance on any test of mental ability could be explained by several cognitive factors organized hierarchically as one general factor and several subordinate specific factors (Spearman, 1904, 1927). The general factor accounted for the significant amount of inter-correlation between all ability tests for any one…

The ability to graphically depict objects in two- and three-dimensional space is fundamental to engineering design practice. Historically, engineers have used pencil, paper, and erasers to draft preliminary sketches and to transform initial drafts into precise production drawings. With the proliferation of computer-aided design (CAD) software…

Cubic symmetry is used to build the other four Platonic solids and some formalism from classical geometry is introduced. Initially, the approach is via geometric construction, e.g., the "golden ratio" is necessary to construct an icosahedron with pentagonal faces. Then conventional elementary vector algebra is used to extract quantitative…