Place a 12" square piece of ice on a plank of Foam

Multiply 12" x .29 & you get 3.48" (use 12" because that is the width of the square)

Set your layout jig for 3.5" & scribe the 4 lines.

Using a chainsaw, cut right on the outside edge of the lines

Using a pistol grip sander, smooth all of the flat surfaces

The finished Octagon

This bar was made with- Cylinders, Octagons & Rectangles