Objects of the same size must be drawn smaller as they move closer to the vanishing point to maintain the illusion of distance. Quick Exercise: The Floating Box Draw a horizontal line across your page (Horizon). Put a dot in the middle (Vanishing Point). Draw a simple square anywhere above or below that line.
Use a ruler to connect the corners of that square to the dot.
This is a specific point on the horizon line where parallel lines appear to meet and disappear.
Draw a smaller square "inside" those lines to cut off the back of the box.
This is the most important line in your drawing. It represents your eye level.