4-point perspective study
How to do this in Photoshop, some ask...
1. Establish horizon (eg middle)
2. Establish 1st and 2nd Vanishing Points (eg, left and right)
3. Your 3rd and 4th Vanishing Points usually lie on the top and bottom of the center eclipse. Create 1 eclipse at the center of this horizon, then duplicate the eclipse and shrink it inwards towards the center. Repeat this until you have the smaller eclipse in the center of the horizon.
4. Draw lines from 1st VP equal distance from each other vertically.
5. Now draw lines from 2nd VP, intersecting each line from 1st VP along vertical-center of eclipse.
Your vertical lines for every object drawn will now be along the curved surface of the eclipses. Straight horizontal lines should be from the 1st and 2nd VPs. Use top/bottom planes to guide horizontal lines, use curved eclipse lines for guiding vertical lines.
Have fun!