In this earlier question the OP asked the following problem:
Given a rectangular grid where some squares are empty and some are fille
1x3 tiles are hard by reduction from cubic planar monotone One-in-three 3SAT. We have to build some "circuitry" to encode the formula.
"Gates":
X********Y
Forces exactly one of X and Y to be covered externally. Used to link a variable and its negation.
Y***
*
*
ooo ****
* * * *
* * * *
X **** Z
Forces none or all of X and Y and Z to be covered externally. Used to copy X or destroy three copies of the same thing. Wires can be shaped more or less arbitrarily using length-3 L pieces.
*******************
* * *
* * *
X Y Z
Forces exactly one of X and Y and Z to be covered externally. One for each clause.