[valid]=Check_L_Tri(L_Tri)

function [valid]=Check_L_Tri(L_Tri)

valid=0;

%General Case
for ii=1:4    
    [x y v]=find(L_Tri(ii,:)~=0);
    row(ii)=sum(v);
end

for ii=1:4    
    [x y v]=find(L_Tri(:,ii)~=0);
    col(ii)=sum(v);
end

if sort(row)==sort(col),  valid=1;  end

%Symmetrical Distribution (exception)
[x y v]=find(L_Tri==0);
if (max(x)-min(x)>1 && max(y)-min(y)>1),  valid=0;  
else  valid=1;
end

%Unusual exception
if max(x)==min(x) || max(y)==min(y),  valid=0; end