Wrebbit 3D Puzzles also known as Puzz-3D, the 3 Dimensional Jigsaw puzzles are made with a new styrofoam core panel backing design, which makes the Piece 3-D Jigsaw Puzzle thicker, lighter and able to cling the puzzle pieces together better in the vertical construction of the puzzle project. The new styrofoam core panel backing "PERFALOCK" design of these puzzles also makes near seamless fits for flat jigsaw puzzles and makes moving the flat jigsaw puzzles more stable, even when hanging them vertically on a wall. Wrebbit Puzzles is famous for its Building Tower Puzzles. These 3D Puzzles are made to Scale. This is the best collection of collectible 3D Puzzles of Famous City Towers, Skyscrapers and Landmarks available.