 Since we have that for this complete configuration the square being scanned by \(T_{\textrm{Simple}}\) is one that was not included in the previous complete configuration (viz. \(T_{\textrm{Simple}}\) has reached beyond the rightmost previous point) the complete configuration as written out by U is in fact incomplete. This small defect was corrected by Post (Post 1947) by including an additional instruction in the function used to mark the complete configuration in the next round.