The present invention provides a three-dimensional user interface for a computer system that allows a user to combine and store a group of windows as a task. A first-conductivity-type transistor included in the high-speed IF circuit block is formed in a second-conductivity-type well, and a second-conductivity-type transistor included in the high-speed IF circuit block is formed in a first-conductivity-type well formed in a second-conductivity-type substrate to enclose the second-conductivity-type well. The first reconstructed image is segmented, and known optical properties of the object are then mapped to the first reconstructed image. water depth, time of submersion, or a combination thereof. The spacer includes a handle with at least one pipe-engaging support member for maintaining an engaged pipe close to a surface in a piping system. The printed circuit board is advantageous in that, since a strike-type through body is externally inserted in a substrate, conventional complicated processes, such as hole forming, deburring, desmearing, electroless copper plating and electrolytic copper plating, can be omitted, thus simplifying a process of manufacturing a printed circuit board and reducing the manufacturing cost thereof.