The Simple Proof of the Tetris Lamp
A few things:1) Why limit yourself to 4x7?  The 1988 NES version of Tetris is 10 units wide.2) There isn't any malicious design, you simply get 1 of each shape (one of the L pieces in the author's photo is reflected, should be turned the other way).3) In Tetris, a full row is removed immediately so having a complete rectangular shape that occupies the full available width is unrealistic.Pedantry aside, you'd have to ask Alexey Pajitnov if there was any devilry involved in choosing the shapes since the makers of the lamp have faithfully included a full set.  Also, I personally prefer the aesthetic of a lamp arranged in such a way as to leave a hole in each row rather than a plain wall of coloured squares.