Perspective studies Just a drawing. Start with an imige of tetrahedron projected on a square on a plane and just dance with Glen Gould playing Art of Fugue or Esperanza with her accoustic waves of love. Geodesics of phenomena of drawing. Riemann curvature tensor is gravity itself. So I fall, fall freely with the lines into the phenomena. Construction of a bijection beetwen X and Y.Let functions f: X -> Yand g : Y -> Xbe injective.Horseshue would represent the set Y\f(X)and a ractangle the set X\g(Y).The bijection is an identification of a set of horssue and its all images via fg with set of images via g of all those horseshues. Simillarilly we can identify a pyramid of ractangles with its back image of f (the smaller pyramid). It looks as a translation on the pyramid of ractangles, just like in Hilberts Hotel (every one goes to his neighbour) and there is infinity of them. Cracovian square market after surgery. One side was cut leaving an infinite triangle as a square market (or a hexagon if we don’t count streets).Study of perspective on curved spaces. Three vanishing points. A triangle horison. World curved positively. One singular point with three fold symmetry. Threefold, fivefold and sixfold symmetry points in a perpendicular line structures. Playfullness in shape of imagined and perceived living space using perspective study of perpendicular lines.