function b = sAND(varargin)
b = true;
for k = 1:numel(varargin)
    if ~varargin{k}();
        b = false;
        return;
    end
end
end

function b = sOR(varargin)
b = false;
for k = 1:numel(varargin)
    if varargin{k}();
        b = true;
        return;
    end
end
end