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- Use a ruler to draw a short, straight vertical line somewhere below the horizon line, in between the two vanishing points.
- Now, use a ruler to draw four straight lines connecting the top and bottom of your line to the vanishing points, like this.
- Draw two more vertical lines, one on each side of your first vertical line, connecting the last lines that you drew, like in this example.
- Use your ruler to draw two more lines, connecting the tops of the lines you drew to the vanishing points on the opposite sides, like in this example.
- Now, erase the horizon line and all lines that are outside of the box.