I wish I knew were the blockage is, I'm probably not using the right words.

When I said "posted" I meant on my main site.
How to find it?
Go to the first index page.
http://www.realcolorwheel.com/
At the top is a Search box that says, "Search a word or topic on the Real Color Wheel site"
type in Perspective bar tool. A list of pages where it is mentioned will be given.
I found this link which has a drawing on how it is used.
http://www.realcolorwheel.com/perspective.htm

Or go the "trunk" of the tree and search for it on that page in the Edit>Find
http://www.realcolorwheel.com/final.htm.
I did that and it highlighted this.
THE ARTISTS' TOOLS OF TECHNIQUE
1998 Perspective Bar Tool

A piece of equipment is used to plot two vanishing points 90 degrees apart and can extend to ten foot for larger paintings. A bar attaches to the back of the painting, level and behind the picture's horizon line. It has hard arms on pivots that clip onto the bar and lock down on the vanishing point. Sometimes times both vanishing points are off the page in a 60 degree picture

I just match up the buildings most extreme top angle with the arm and clip it on the horizon bar by matching the angles of the arm bar to the image. Look at the building and point to the extended vanishing point to the left or right of my picture, that where I clip the arm on and where that square building's vanishing point goes to. That position works now for any building in my picture with those compass angles.

Hi Rency, I posted how you can make it with a yard stick and some clothespins. You don't need to buy it.