Straightness and symmetry; straightness on a sphere; what is an angle?; straightness on cyliner and cone; SAS and ASA; area, parallel transport and holonomy; ITT, SSS and ASS; parallel transport; SAA and AAA; parallel postulates; 3-spheres in 4-space; dissection theory; square roots, pythagoras and similar thoughts; geometric solutions of quadratic and cubic equations; projections of a sphere onto a plane; duality and trigonometry; isometries and patterns; polyhedra. Appendices: geometric introduction to differential geometry; geometry for me.
