Drawing a Square in One Point Perspective
Perspective study of a method for drawing a correctly proportioned square in one point perspective. The regular square ACDE is projected onto a target perspective square parallel to the horizon plane. Dragging point A and point C respectively repositions and changes the source square's size. Moving point B adjust the target square's height above or below the horizon. By right clicking the target square, setting trace, and manipulating the height, position and size controls, you can create a groovy 3d composition with a variety of architectural towers at different apparent distances from the viewer.
Source Credit:
Art Studio Chalkboard. 'Plotting a Perfect Square in 1-Point Perspective'.
http://studiochalkboard.evansville.edu/lp-square.html .