This chapter explores cases in which the projection plane p is parallel to one of the coordinate planes, particularly focusing on xy. It examines the simplifications and visual effects produced by this condition and offers a detailed analysis of the representation and reading of points, lines, and planes. Through geometric constructions, the text presents how to identify traces, intersections, and projections of spatial elements under specific obliquity conditions. Practical exercises guide the reader through the interpretation of drawing distortions and projection-induced transformations. The chapter also highlights the challenges of interpreting spatial data in a flat image.