How to create a quick sketch of a simple two point perspective castle

When a round form (cone or cylinder) is above the horizon line, it appears to curve up.  

If it is below the horizon it appears to curve down (because you are looking down at it).

In this picture, the top of the tower is above the horizon and the bottom of the tower is below the horizon.

The horizon line is always at the same level as the viewer’s eye or the camera.  

 For this reason, it is also known as the ‘eye level’ line  or the ‘camera line’.

Print out a copy of the two point perspective grid and try drawing a simple castle. Then try sketching a castle without the grid. Add details, like a moat or a drawbridge. Be as creative as possible. If you would like to add people, start by adding one person standing near the door. Make sure the figure is small enough to fit into the doorway. Draw people in the foreground larger and lower on the page and people in the background smaller and closer to the horizon.