wgetch

    #const d=3.
    #const n=d*d.
    
    1 { s(X,Y,1..n) } 1 :- X=1..n, Y=1..n.
    % Achieved: A value is chosen for each cell

    X1=X2 :- s(X1,Y,N), s(X2,Y,N).
    Y1=Y2 :- s(X,Y1,N), s(X,Y2,N).
    % Achieved: No value is duplicated for any given row or column

    r(X,Y,Z) :- X=1..n, Y=1..n, Z=((X-1)/d)*d+((Y-1)/d)+1.
    (X1-X2)*(X1-X2)+(Y1-Y2)*(Y1-Y2)=0  :- s(X1,Y1,N), s(X2,Y2,N), r(X1,Y1,Z), r(X2,Y2,Z).
    % Achieved: No value is duplicated within a d*d region

    #show s/3.

    hash -d hello=~/Documents
    ~hello/world