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The two-hole tetrominoes were invented by Kate Jones. Use the ‘double-perforated’-tetrominoes to make a fence on a plane, where the enclosed area is one part.
The tetrominoes have to touch by at least one full side. (corner-connection is illegal).
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Kadon Enterprises(the company of Kate Jones) makes the two-hole tetrominoes under the name "Fill-Agree".
The touching squares of the different tetrominoes have to be either both ‘holey’ or both ‘unholey’.
Try to maximize the enclosed area.
In the example below the enclosed area is 225. This solution was made as an example by Pieter Torbijn from Den Haag. Pieter is 78 and has been involved with tetrominoes (and other polyforms) his entire life.
