Rockland Breakwater lighthouse -students' practices and final drawings, adult art class, 8/10/15. And the reference photo, my pic from a ferry trip in 1999? Practices were done by following along with my demo drawing. No real explanation of perspective principles. Just a loose run through of what actual shapes we were seeing and what else they might look like. You might be able to find an example of the very first practice - drawing a skewed cube vs. a normal cube, just by coloring in shapes using invisible outline. Tough habits to break when one is so used to thinking in terms of outlines. Yes, outlines are very important - BUT you also need to practice a feel for areas and imaginary outlines.
The clock wall displays the final drawings, done as desired.