DesarguesPappus

This application helps students and teachers explore classic theorems by directly drawing and manipulating configurations on a plane, rather than just reading formulas. Place two triangles in the perspective view of the Desargues module. Drag any vertex, and the application will update the perspective center and axis, verifying that concurrent connection lines and collinear side intersection points remain equivalent. Pappus arranged two collinear triplets and highlighted Pascal lines at the intersection. Duality switches between point view and line view through clear association tables. Calculate invariants (A, B; C, D) for cross ratio, and plot homogeneous points and lines ax+by+C=0 in the coordinate laboratory to test the incidence rate. Each screen provides presets, grid and stroke control, manual coordinate input, and real-time status feedback.