I just completed building a floating deck. It is shaped like a trapezoid, due to the angle of my driveway. The deck is 22.25' on the longest side. The opposite, parallel side is 17.5' long. The width of the deck is 16.5' The back side is perpendicular to the parallel sides. The angled side runs along the driveway. My lawn is very uneven terrain. The deck is supported by 9 concrete pillars that are 1 foot in diameter. At the lowest corner, nearest the house, the deck is one step above the sidewalk. The deck is 18 inches off the ground at the highest corner, diagonally across from the lowest corner. A 16'x16' pergola would have 3 of the corner posts or columns directly above concrete pillars, and the deck frame, underneath the decking boards. Cinderblocks provide additional support under the frame where the 4th pergola corner post/column would be. The pergola has an elaborate, multi-tiered, open design, would use 2" x 12" girders, but shouldn't weigh much more that a plain pergola of the same size. At each corner of the pergola, there would be three (3) 6"x6" posts 4' apart making an "L" arrangement, with added lattice structure on each "L". Cutting through the deck for the post is not a realistic option. So, how do I attach the post to the deck to withstand the various pressures and to be aesthetically pleasing, as well?