results ns = [res | (ls,rs) <- split ns,
                    lx       <- results ls,
                    ry       <- results rs,
                    res      <- combine' lx ry]
results ns = [res | (ls,rs) <- split ns,
                    lx       <- results ls,
                    ry       <- results rs,
                    res      <- combine' lx ry]
results ns = [res | (ls,rs) <- split ns,
                    lx       <- results ls,
                    ry       <- results rs,
                    res      <- combine' lx ry]